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Development of light transmitting mortar

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Title:
Development of light transmitting mortar
Creator:
Lampton, Jason ( author )
Place of Publication:
Denver, Colo.
Publisher:
University of Colorado Denver
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Language:
English
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1 electronic file (120 pages) : ;

Thesis/Dissertation Information

Degree:
Master's ( Master of science)
Degree Grantor:
University of Colorado Denver
Degree Divisions:
Department of Civil Engineering, CU Denver
Degree Disciplines:
Civil engineering

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Subjects / Keywords:
Fiber optics ( lcsh )
Masonry ( lcsh )
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bibliography ( marcgt )
theses ( marcgt )
non-fiction ( marcgt )

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Review:
Translucent, or sometimes called transparent, concrete is a fairly new concrete based building material with light-transmissive properties due to embedded optical fibers into normal cement mix. This report takes this concept to the next level by successfully developing Light Transmitting Mortar, or further referred to as LTM. Like translucent concrete, where light is conducted through concrete blocks from one side to the other through fiber optics, this idea lays optical fibers within the mortar of brick prisms to test the physical and mechanical properties. Although the idea of LTM is thought to be mainly architectural, tests demonstrate that it actually increases the strength of the overall assemblages pretty substantially. This added benefit combined with many possible eye-catching patterns, once lights are placed behind or within the cavity of brick veneer walls, will open the door to many new and stimulating possibilities for future architects and engineers.
Bibliography:
Includes bibliographical references.
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System requirements: Adobe Reader.
Statement of Responsibility:
by Jason Lampton.

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Source Institution:
University of Colorado Denver
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Auraria Library
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All applicable rights reserved by the source institution and holding location.
Resource Identifier:
on10218 ( NOTIS )
1021886101 ( OCLC )
on1021886101
Classification:
LD1193.E53 2017m L36 ( lcc )

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Full Text
DEVELOPMENT OF LIGHT TRANSMITING MORTAR
by
JASON LAMPTON B.S., Texas A&M University, 2003 M.S., University of Colorado, 2017
A thesis submitted to the Faculty of the Graduate School of the University of Colorado in partial fulfillment of the requirements for the degree of Master of Science Civil Engineering Program
2017


Jason Lampton
All Rights Reserved


This thesis for the Master of Science degree by
Jason Lampton
has been approved for the
Civil Engineering Program
by
Frederick Rutz, Chair Kevin Rens Peter Marxhausen
Date: December 16, 2017
m


Lampton, Jason (M.S., Civil Engineering Program)
Development of Light Transmitting Mortar Thesis directed by Associate Professor Frederick Rutz
ABSTRACT
Translucent, or sometimes called transparent, concrete is a fairly new concrete based building material with light-transmissive properties due to embedded optical fibers into normal cement mix. This report takes this concept to the next level by successfully developing Light Transmitting Mortar, or further referred to as LTM. Like translucent concrete, where light is conducted through concrete blocks from one side to the other through fiber optics, this idea lays optical fibers within the mortar of brick prisms to test the physical and mechanical properties. Although the idea of LTM is thought to be mainly architectural, tests demonstrate that it actually increases the strength of the overall assemblages pretty substantially. This added benefit combined with many possible eye-catching patterns, once lights are placed behind or within the cavity of brick veneer walls, will open the door to many new and stimulating possibilities for future architects and engineers.
The form and content of this abstract are approved. I recommend its publication.
Approved: Frederick Rutz
IV


TABLE OF CONTENTS
CHAPTER
I. INTRODUCTION..................................................... 1
II. LITERATURE REVIEW................................................ 3
2.1 Translucent Concrete: An Emerging Material.................... 4
2.2 LiTraCon Light Transmitting Concrete........................ 7
2.3 An Experimental Study on Light Transmitting Concrete.......... 10
2.4 Light Transmitting Concrete Panels A New Innovation
in Concrete Technology......................................... 17
2.5 Mortar this than meets the eye: The 'transparent' cement
that lets daylight flood into a room........................... 19
2.6 A preliminary study on light transmittance properties of
translucent concrete panels with coarse waste glass inclusions. 21
2.7 Experimental Study of Transparent concrete (translucent)...... 23
2.8 Computational Modeling of Translucent Concrete Panels......... 25
2.9 Development, Testing, and Implementation Strategy of a Translucent Concrete-Based Smart Lane Separator for
Increased Traffic Safety....................................... 27
III. PROBLEM STATEMENT............................................... 31
IV. EXPERIMENTAL PLAN............................................... 32
4.1 Properties of Light Transmitting Mortar....................... 34
4.1.1 Fiber Volume Ratio......................................... 34
4.1.2 Optical Fibers............................................. 36
v


4.1.3 Mortar Design Mixture.................................... 38
4.2 Manufacturing Methods.......................................... 39
4.2.1 Setup and Preparation..................................... 40
4.2.2 Building the Prisms....................................... 41
4.2.3 Grinding and Polishing.................................... 44
4.3 Testing Methods................................................ 45
4.3.1 Light Transmittance Test.................................. 46
4.3.2 Compressive Strength Test................................. 48
4.3.3 Shear Strength Test....................................... 50
V. RESULTS........................................................ 53
5.1 Light Transmittance............................................ 53
5.2 Compressive Strength........................................... 56
5.3 Shear Strength................................................. 58
VI. CONCLUSION..................................................... 61
6.1 Manufacturing Methods.......................................... 61
6.2 Light Transmittance............................................ 62
6.3 Compressive Strength........................................... 63
6.4 Shear Strength................................................. 65
6.5 Final Thoughts................................................. 66
REFERENCES................................................................... 67
APPENDIX..................................................................... 69
A. Light Transmittance Test (Varying Fiber Volumetric Ratio) Photos. 69
B. Light Transmittance Test (Equal Fiber Volumetric Ratio) Photos... 72
vi


C. Compression Test (Varying Fiber Volumetric Ratio)-Photos.......... 74
D. Compression Test (Equal Fiber Volumetric Ratio) Photos.......... 77
E. Prism Compression Data Varying Fiber Volumetric Ratio............ 79
F. Prism Compression Data Equal Fiber Volumetric Ratio.............. 91
G. Mortar Cube Compression Test Photos.............................. 99
H. Mortar Cube Compression Data.......................................100
I. Shear Test Photos............................................... 102
J. Shear Test Data................................................... 106
vii


LIST OF TABLES
TABLE
4.1.1 Volumetric Ratio Design Table.....................................35
4.1.3 Mortar type for some general applications.........................38
5.1 Light Transmittance Test Results..................................54
5.2 Compressive Strength Test Results.................................56
5.3 Shear Strength Results............................................60
viii


LIST OF FIGURES
FIGURE
1 Light Transmitting Mortar.................................................. 2
2.1 Translucent Concrete used in art installations in museum exhibits..... 5
2.2.1 Components of Optical Fiber........................................... 7
2.2.2 Examples of Light Transmitting Concrete............................... 8
2.3.1 Types of Optical Fiber................................................12
2.3.2 Compressive Strength................................................. 14
2.3.3 Flexural Strength.................................................... 15
2.4 Lucem light transmitting concrete panels................................ 17
2.5.1 Outside view of Italian Pavilion for the Shanghai Expo............... 19
2.5.2 Tiny resin filled holes.............................................. 20
2.5.3 Inside of Italian Pavilion for the Shanghai Expo..................... 21
2.6 Light Transmitting Panel Built with Waste Glass...................... 22
2.7 Schematic layout of a molded block with fixed
fiber composites within the framework.................................24
2.8 A computational model of transparent concrete panel...................26
2.9 Functional description of proposed smart lane separator...............28
4.0 The making of mortar cubes...............................................33
4.1.2 Optical Fiber Principles..............................................37
4.2.1 Machine at All cable, Inc. to cut fiber to length.....................41
4.2.2- 1 Building a typical mortar joint with fiber optics..................42
4.2.2- 2 Keeping it consistent..............................................43
IX


4.2.3 Grinding & Polishing.................................................45
4.3.1- 1 Light Transmittance Test Box Diagram.............................46
4.3.1- 2Light Transmittance Test Box......................................47
4.3.2 Testing the Compression Strength of a Prism.......................48
4.3.3- 1 Shear Test Setup.................................................51
4.3.3- 2 Shear Failure Patterns...........................................52
5.1- 1 Inside the Light Test Box.........................................53
5.1- 2 Light Transmittance vs. Fiber Volumetric Ratio.....................55
5.1- 3 Light Transmittance vs. Fiber Optic Diameter...................... 55
5.2- 1 Compressive Strength vs. Fiber Volumetric Ratio................... 57
5.2- 2 Compressive Strength vs. Fiber Weight Ratio....................... 57
5.2- 3 Compressive Strength vs. Fiber Optic Diameter..................... 58
5.3- 1 Results of Shear Failure...........................................59
5.3- 2 Bond Shear Strength vs. Fiber Volumetric Ratio.................... 60
6.3- 1 Failure Mode in Brick Prism........................................64
6.3- 2 Tensile Splitting during Compression testing.......................64
x


LIST OF EQUATIONS
EQUATION
2.3- 1 Compressive Strength...........................................14
2.3- 2 Flexural Strength............................................. 15
4.1.1 Fiber Optic to Mortar Volumetric Ratio........................ 34
4.3.1 Light Transmittance Percentage................................ 47
4.3.3 Bond Shear Strength........................................... 51
xi


CHAPTER I
INTRODUCTION
The purpose of this thesis will be to analyze the mechanical performance and physical properties of varying the diameter and volumetric ratios of optical fiber to mortar while developing a method to manufacture Light Transmitting Mortar (LTM). Specifically, this thesis analyzes the use of four different diameters of fiber optics (1.0 mm, 1.5 mm, 2.0 mm, and 3.0 mm) to determine such properties as light transmittance, compressive strength, and shear strength. A control sample without the addition of fiber optics was also tested to serve as a benchmark for the results.
There are two primary purposes for conducting this experiment. The first purpose is to develop a new and innovative product where light can be seen through a wall along the mortar joints. As it will further be discussed in the literature review section of this report, Translucent Concrete was invented in 2001 and has been developed by commercial companies over the past decade. However, there was no mention in the literature of this idea ever being expanded into the mortar between the masonry units of masonry construction.
The main reason this has thought to be true is fact that mortar is typically applied onsite, or in the field, and the process of stringing fiber optics effectively in cast concrete has only been proven to be done in manufacturing plants or laboratories. I believe that after showing there are positive properties in the process of laying individual short-length fiber optics in the mortar between bricks, a fiber optic mesh can be created to make the process faster and easier in the field. Although the main purpose of creating LTM is thought to be architectural, it turns out there may be other beneficial properties as well.
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The second purpose of the experiment is to determine the mechanical performance and physical properties of adding fiber optics specifically into the mortar between typical clay brick masonry units. Through a literature review of translucent concrete, it was found that adding fiber optics to concrete slightly increased the strength of the product. However, this report will show that the addition of fiber optics substantially increases the compressive strength to a completed masonry assemblage. Typically, a masonry assemblage is thought to be stronger than its weakest component (mortar) and is weaker than its strongest component (the brick units). With the addition of fiber optics to this new composite material, this idea continues to be true but gives the added bonus of being able to transmit light through the mortar.
Figure 1: Light Transmitting Mortar
2


CHAPTER II
LITERATURE REVIEW
The literature review of this report is based mainly on the findings and usage of translucent concrete as it is the most comparable product to LTM and no research could be found on placing fiber optics into the mortar between masonry units. The term translucent concrete has the potential to be somewhat misleading. The concrete itself is not actually translucent, nor is it any different to conventional concrete. Translucent concrete simply contains fiber optics which has the capacity to transmit light from one side to the other of the pre-fabricated blocks. Perhaps a more suitable term could be light transmitting concrete.
It is important to differentiate this, as past attempts have been made to create an actual translucent concrete. Such attempts have generally proven unsuccessful as the product becomes fragile, and incapable of withstanding wind and rain (Goho, 2005). Thus, the continuation and development of this idea has led to the creation of Light Transmitting Mortar.
Aron Losonczi, first introduced the idea of light transmitting concrete in 2001, then produced the first homogeneous translucent concrete block and named his company Litracon in 2003. In his process, the translucent concrete blocks are manufactured by layering optical fibers and concrete mix to form a truly homogenous material. It can be used for interior or exterior walls, illuminated pavements or even in art and design objects. Litracon claims their concrete has the same strength as regular concrete, if not even slightly higher, and will continue to transmit light through walls up to twenty meters thick (Ali, 2014). Thousands of optical glass fibers run parallel to each other between the two main surfaces of every block so
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shadows on the lighter side will appear with sharp outlines on the darker one. Even the colors remain the same. This special effect creates the general impression that the thickness and weight of a concrete wall will disappear.
The idea of LTM uses many of the same ideas found in the journals and articles to follow, as the concept is very similar to translucent concrete. Like translucent concrete,
LTM is thought to be best suited for interior walls or art and design objects such as benches or an architectural accent wall. The basic idea behind LTM will be to place a LED wall wash light-bar, often found in bars or night clubs, in a small cavity behind the brick wall or bench. The use of spot lights to illuminate desired patterns and designs from an area on the opposite side of an interior wall could also provide an interesting way to allow light to come through its mortar joints. The hope is that this new material will transform the interior, and possibly exterior, appearance of masonry construction by bringing them to life through illuminating mortar joints with a multitude of colors, designs, and shapes.
2.1 Translucent Concrete: An Emerging Material (McGillivray, 2011)
In this article, Sara McGillivray dives into the idea, the history and the future of translucent concrete. When you think of concrete, most likely, your mind conjures up images of something solid, heavy, and monolithic. But what if concrete could be translucent and transmit light into spaces, making them seem light and airy (McGillivray, 2011)? This article states that by switching the ingredients of traditional concrete with transparent ones, or embedding fiber optics; translucent concrete has become a reality.
Concrete has been called an indispensable medium and a quintessential material for architects and engineers due to the vast sculptural and expressive possibilities that it can
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achieve. Concrete has been used since Roman times, but its basic components have remained the same. Three ingredients make up the dry mix: coarse aggregate, fine aggregate, and cement (The Economist, 2001). By switching ingredients and adding new ones, engineers have been able to create a multitude of interesting new products, one of which is translucent concrete (Goho, 2005). In the early stages of creating translucent concrete, they simply exchanged the traditional aggregates and the bonding material itself with transparent alternatives to be able to transmit light through clear resins in the mix.
(Luxgineer Wiki media Common)
Figure 2.1: Translucent Concrete used in art installations in museum exhibits
A more modem and second approach discussed in this article is the combination of optical fibers and fine concrete. This method of producing translucent concrete has been more fully explored and is more common to date than the previous method. This method, originally explored by the Hungarian Architect, Aron Losoncze, uses very fine aggregate to encase optical fibers that allow light to transmit from one side of a block to the other. However, the process is slow and done by hand in a long, narrow mold. The optical fibers and concrete must be manually layered over each other to create a long beam that will eventually be cut into blocks. The blocks from Losonczes approach can retain their strength
5


and bond because the proportion of the fibers is very small (4%) compared to the total volume of the blocks (Ali, 2014). They are not reinforced in the traditional sense, since the optical glass fibers form a matrix which creates an internal structure of reinforcement. Losonczes optical-fiber concrete blocks claim a higher compressive strength of 7,252 psi and a surprising tensile strength of 1,015 psi (Ali, 2014). His tests show that glass fibers do not have a negative effect on the well-known high compressive strength value of concrete. Rather, fiber reinforcing can make translucent concrete even stronger than traditionally reinforced concrete.
It has also been found that translucent concrete can be an insulating material, protecting against outdoor extreme temperatures while also letting in daylight. This makes it an excellent compromise for buildings in harsh climates, where it can shut out heat or cold without shutting the building off from daylight. In the next few years, as engineers further explore this exciting new material, it is sure to be employed in a variety of interesting ways that will change architecture and engineering as we know it.
The article did cover some of the negatives or down sides to translucent concrete and currently the cost to manufacture these products tops the list. It was stated at the time of this article that it could end up costing about five times as much to build a wall using translucent concrete as opposed to the traditional type (The Economist, 2001). This is due to the rarity of the product and its experimental nature. Currently, there are only a select few companies around the world producing translucent concrete and the process is somewhat low-tech and slow. At the time of this article, it was said that it can only be produced as pre-cast or prefabricated blocks and panels. Thus, it is mostly being used in interior walls and as decoration, but it is starting to make its venture into exterior structural walls.
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2.2 LiTraCon Light Transmitting Concrete (Ali, 2014)
In 2001, a light-transmitting concrete block was invented by Aron Losonczi, an architect from Hungry. He named his invention LITRACON, short for light transmitting concrete and has sold commercial grade precast manufactured translucent concrete blocks since 2003. LiTraCon has become the leader in the translucent concrete development and currently holds the patent on the material. This review is based on a slideshow/seminar linked to LiTraCons website and outlined key points of their invention.
As most of us know, concrete is one of the worlds most widely used building materials and builders have been using concrete for thousands of years. However, the introduction of fiber optics into the concrete mix has given it a new dimension and we are just at the beginning stages of the development of translucent concrete. To understand Losonszis method of creating translucent concrete, we need to explore the basic component, optical fibers, needed to create the matrix of fiber and cement within these light-transmitting blocks. An optical fiber is a flexible, transparent fiber made up of glass or plastic and is often as thin as a human hair. It transmits light between two ends of the fiber by process of total internal reflection and does it so effectively that there is almost no loss of light conducted outside the fibers. The optical fiber is made up of three components:
Cladding
Glass Core
Plastic
Protective Coating
(http://www.webclasses.tiet/3comu/wtro/miits/miit02/sec04b.html) Figure 2.2.1: Components of Optical Fiber
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1. CORE (carries light signals) thin glass center of fiber where light travels
2. CLADDING (keeps light in the core) made of a material which has a lower refractive index than the core, (for light to pass from the core out through the cladding, it would have to slow down. Instead, the light waves take the path of least resistance by reflecting only in the core.)
3. COATING (protects the cladding) Plastic coating that protects the fiber from damage.
LiTriCons light-transmitting concrete is produced by adding 4% to 5% optical fibers (by volume) into a concrete mixture (Ali, 2014). The fibers need to run parallel to each other and the most important requirement for the success of the product is the assurance that the fiber optic strands contact both surfaces; otherwise it loses the ability to transmit light. An uninterrupted passage through the concrete is achieved by using long molds; which are filled with a thin layer of cement, then strung layers of fiber optic strands atop the cement, then more cement is added and the process is repeated until the mold is full. From the long molds, the product can be removed and then cut to length accordingly to make the size of blocks
(Ali, 2014)
Figure 2.2.2: Examples of Light Transmitting Concrete
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LiTraCon believes that light transmitting concrete or translucent concrete is an emerging trend in concrete technology and has created a short list of its advantages, disadvantages and applications that they have found over the years of production:
ADVANTAGES:
1. Less energy consumption.
2. Illuminated pavements and roads for safety.
3. Homogeneous in structure.
4. Finishing surface.
5. Routine maintenance not required.
DISADVANTAGES:
1. Very high cost (about EUR 1300/m2)
2. Laborers with technical skills are needed to use it.
3. Its a factory product.
APPLICATIONS:
1. Sidewalks poured with translucent concrete could be made with lighting underneath, creating lit walkways which would enhance safety, and also encourage foot travel where previously avoided at night.
2. Translucent concrete walls on restaurants, clubs, and other establishments to reveal how many patrons are inside.
3. Translucent concrete inserts on front doors of homes, allowing the resident to see when there is a person standing outside.
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4. The use of translucent concrete in an outer wall of an indoor stairwell would
provide illumination in a power outage, resulting in enhanced safety.
5. Subways using this material could be illuminated with daylight.
Not only can translucent concrete be used in the applications above, but its also a green building material because it can reduce the lightning cost during day time (Ali, 2014). On top of this perk, it has been found to provide both an aesthetically pleasing appearance and structural stability. The LiTraCon blocks claim to be able to be used as load bearing walls up to 20 meters high (Ali, 2014). If the price of the product gets reduced, it is sure that the future of the construction industry will be in the hands of Litracon.
2.3 An Experimental Study on Light Transmitting Concrete (Shanmugavadivu, et al, 2014)
This article was very helpful in giving specific numbers and explanations of what exactly goes into light transmitting concrete. In the light transmitting concrete discussed in this article, optical glass fibers were thought to form a matrix and run parallel to each other between the two main surfaces of a block. The fibers mingle in the concrete because of their insignificant size and they become a structural component as a kind of modest aggregate.
The material make-up of these blocks can be broken down into these 4 components:
1. CEMENT As the optical fiber is only responsible for transmission of light, there is no special cement required. So, ordinary Portland cement is typically used for transparent concrete.
2. SAND A naturally occurring granular material composed of finely divided rock and mineral particles. The composition of sand is highly variable, usually in the
10


form of quartz. Sand particles should pass through 1.18 mm sieve. (The sand used should be free from impurities such as vegetation and gravels.)
3. WATER When mixed with cement, it forms a paste that binds the aggregate together. The water needs to be pure to prevent side reactions from occurring, which could weaken the concrete. The role of water is important because the water to cement ratio is the most critical factor in the production of "perfect concrete.
4. OPTICAL FIBERS An optical fiber is a flexible, transparent fiber made of glass (silica) or plastic to a diameter slightly thicker than that of a human hair. Optical fibers are used most often as a means to transmit light between the two ends of the fiber.
Light transmitting concrete is a combination of optical fibers and fine concrete that are typically produced as prefabricated building blocks and panels. By arranging thousands of Plastic Optical Fibers (POF) or big diameter glass optical fibers into concrete, it transmits light so effectively that there is virtually no loss of light conducted through the fibers.
Because of their parallel position, the light-information on the brighter side of such a wall appears unchanged on the darker side. The most interesting form of this phenomenon is probably the sharp display of shadows on the opposing side of the wall. Moreover, the color of the light also remains the same.
Light travels through the fiber core, bouncing back and forth and off the boundary between the core and cladding. Because the light must strike the boundary with an angle greater than the critical angle, only light that enters the fiber within a certain range of angles can travel down the fiber without leaking out. This range of angles is called the acceptance
11


cone of the fiber. The size of this acceptance cone is a function of the refractive index difference between the fibers core and cladding. Currently, there are three basic types of optical fibers and each vary on how the refractive index between the core and cladding is put together.
Step Index (Multimode)
Cladding Core
Source
Graded Index (Multimode)
Single Mode (Monomode)
(www. cables-solntiom. com) Figure 2.3.1: Types of Optical Fiber
1. MULTI-MODE STEP-INDEX FIBER This fiber is called "Step Index" because the refractive index changes abruptly from cladding to core. The cladding has a refractive index that is somewhat lower than the refractive index of the core. As a result, all rays within a certain angle will be totally reflected at the core-cladding boundary. Rays striking the boundary at angles greater than the critical angle will be partially reflected and partially transmitted out through the boundary. After many such bounces, the energy in these rays will be lost from the fiber. The paths
12


along which the rays of this step index fiber travel differ depending on their angles relative to the axis.
2. MULTI-MODE GRADED-INDEX FIBER In graded index fiber there are many changes in the refractive index with larger values towards the center. Light travels faster in a lower index of refraction. So, the farther the light is from the center axis, the greater is its speed. This means that each layer of the core refracts the light with a different refractive index. Instead of being sharply reflected as it is in a step index fiber, the light is now bent or continuously refracted in an almost sinusoidal pattern. In theory, those rays that follow the longest path by traveling near the outside of the core have a faster average velocity and the light traveling near the center of the core has the slowest average velocity. As a result, all rays tend to reach the end of the fiber at the same time. That causes the end travel time of different rays to be nearly equal, even though they travel different paths.
3. SINGLE-MODE STEP-INDEX FIBER Another way to reduce modal dispersion is to reduce the core's diameter, until the fiber only propagates one mode (ray) efficiently. The single mode fiber has an exceedingly small core diameter of only 5 to 10 pm. Standard cladding diameter is 125 pm. Since this fiber carries only one mode, model dispersion does not exist. A multimode fiber can propagate hundreds of light modes at one time while single-mode fibers only propagate one mode as shown above.
The properties of light transmitting concrete are determined by conducting various experiments like compressive strength and flexural strength tests. A typical transparent
13


concrete block, in the testing of this article, is shown below with mix proportions and dimensions as follows: (Shanmugavadivu, et al, 2014)
Cement-360 kg
Sand 560 kg
Fiber-4.5 kg
Water 190 liter
Size: 150mm xl50mm x 150mm
The compressive strength of a material is that value of uniaxial compressive stress reached when the material fails completely. The compressive strength is usually obtained experimentally by means of a compressive test and using the following equation:
Compressive Strength = P / A
Where:
P = Load applied A = Area of prism
Compressive strength of the concrete
E
(Shanmugavadivu, et al, 2014) Figure 2.3.a: Compressive Strength
14


Flexural strength of the concrete
(Shanmugavadivu, et al, 2014) Figure 2.3.b: Flexural Strength
The compressive strength and flexural strength of the conventional concrete and light transmitting concrete in 7, 14 and 28 days is shown in Figure: 2.3.a and 2.3.b respectfully. The flexural strength of the concrete was determined by conducting the test on a prism by way of two-point loading and using the following equation.
Flexural Strength = Pl/bd2
Where:
P Load
l Length of the specimen b Width of the prism d-Depth of the prism
After the compressive and flexural strength results of the decorative concrete were correlated with the results of ordinary plain cement concrete, the results show that the performance of light transmitting concrete is slightly higher than ordinary cement. Hence,
15


the application of optical fiber will make the concrete structurally efficient as well as decorative. Thus, the study concludes that the transparency of light is possible in concrete without affecting its compressive strength and the optical fibers can act as a fiber reinforcement, thereby enhancing the strength as well as the appearance. This article also listed some other notable properties of the light transmitting concrete found through different tests: (Shanmugavadivu, et al, 2014)
1. Permits the passage of light through the set concrete; permitting colors, shapes and outlines to be seen through it.
2. Having compressive strength of 7,250 32,000 psi
3. Having maximum water absorption of 0.35%
4. Having a maximum oxygen index of 25%
5. Having a thermal conductivity of 0.21 W/m C
6. Having a flexural strength of 1.1 ksi
7. Having an elastic limit greater than 8,700 psi
8. Having a density from 130 to 150 lb/ft3
9. Having a Young's Modulus from 400 ksi to 500 ksi
10. From its characteristics and composition, it can be a conductor of electricity.
11. From its mechanical and optical characteristics, it can be used for purposes that are both architectural and aesthetic, as well as structural.
16


2.4 Light Transmitting Concrete Panels A New Innovation in Concrete Technology
(News Desk, 2013)
This article talks about how German concrete manufacturer, Lucem Lichtbeton, is thought to be one of the other leading companies involved in the production of light transmitting concrete. In conjunction with Aachen-based architects, Carpus & Partner, Lucem produced 150cm by 50cm concrete panels containing optical fibers and placed them along a wall; forming a total area of 30m wide by 4m high with 136 panels. Each panel was fitted with color-changing technology and controlled using an internet-based DMX technology system. The technology controlling the lights opens new boundaries for design and architecture as the light panels are made with red, green and blue chips to allow more than 16 million color options. In fact, all the panels can be controlled independently meaning the entire facade can become a large display screen. The light shows on the wall can be controlled via the internet or a mobile device and interactive elements as well as text and logos can be displayed on this wall (News Desk, 2013).
(www. lucem. com)
Figure 2.4: Lucem light transmitting concrete panels at RWTH Facade, Aachen
17


According to the Lucem website, there are currently three different types of Lucem Lichbeton panels, which offer different effects and aesthetics for the user. These panels have various uses including, but not limited to: facades, interior walls, claddings, flooring systems, room dividers and bars. With the Lucem Label panels, light transmitting fibers are arranged individually so that clients can display design logos, images, names, signatures and icons on the panels. Some additional application areas and examples of Lucem mentioned in this article were (News Desk, 2013):
1. CLINIC GENK (surgical clinic, partition wall) The new building of an oral surgery clinic presents a large-sized Lucem wall used as a room divider. A brightly illuminated waiting area induces an interesting shadow play on the part of the offices.
2. NESSELANDE, ROTTERDAM, OUTSIDE ILLUMINATION (promenade at overpark) In Rotterdams district Nesselande, a local recreation area was created. Long bands of concrete were integrated into the landscape enclosing the greenery on the one side and being a bench on the other side.
3. SIGNAL IDUNA (Extension of the main administration building of Signal Iduna insurances, Dortmund) Lucem light transmitting concrete panels were used as accents for the entrance hall and the executive suite. The Lucem Line panels have been designed as floor to ceiling wall claddings utilizing free space behind the panels for a light supply.
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2.5 Mortar this than meets the eye: The 'transparent' cement that lets daylight flood into a room (Bates, 2011)
In this article, a team of architects have created a new way of making transparent cement panels that lets light pour into a room so that the walls look like giant windows. These Italian architects operate under the company name Italcementi and believe that their research is a strategic asset aimed at creating innovative projects that follow up new market trends. In 2010, they took up the challenge to build the Italian pavilion for the Shanghai Expo because they wanted to find a creative, efficient solution for a cement material to be able to transmit light. They called their invention i-light and its formed by bonding special resins inside of dozens of tiny holes to let light through without compromising the structural integrity. The design is to appear to have its surface transparent from a far, but up close the tiny resin filled holes that make up the panels can be seen.
(www. itcilcementigroap. com)
Figure 2.5.1: Outside view of Italian Pavilion for the Shanghai Expo
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I-light SHANGHAI gets its namesake from its original purpose for the invention, the Italian pavilion. Italcementi used i-light for around 40% of the 18-metre high Expo pavilion. Three thousand seven hundred and seventy-four transparent and semi-transparent panels were made from 189 tons of the product.
There are approximately 50 holes in each transparent panel, leading to about 20% transparency. Its transparent characteristic is not only able to transmit natural and artificial light, but also allows the human eye to see images and objects placed behind the panel. During the day, external light seamlessly filters into the building creating a new and suggestive atmosphere as the sunlight intensity varies throughout the day. At night the effect becomes magical, with internal light seeping back through the panels and making the building become alive. Thanks to this, the architectural structure itself creates a show that has never been seen before.
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(www. itcilcementigroap. com)
Figure 2.5.3: Inside of Italian Pavilion for the Shanghai Expo
Previous attempts at a similar feat had been tried using fiber optic cables, but Italcementi claims its version is better. Enrico Borgarello, Italcementi Group Innovation Director, said: The transparent cement made from plastic resins is much cheaper than the one made from optical fibers. Moreover, the ability to capture light is greater, since the resins contain a wider visual angle than optical fibers (Bates, 2011). The technology used to build i.light panels guarantee a degree of light angle of incidence higher than optical fibers. The cost of i.light is also at least 10 times lower than the same material obtained using optical fibers.
2.6 A preliminary study on light transmittance properties of translucent concrete panels with coarse waste glass inclusions (Pagliolico, et al, 2015)
This paper investigated the use of coarse glass waste imbedded in cement to make precast translucent concrete panels. Waste pieces of glass that were found to have flat and
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coarse physical properties were enclosed and surrounded with a concrete mix to extend from one side to the opposite side of the panel, enabling light transmission through the wall.
(Pagliolico, etal, 2015)
Figure 2.6: Light Transmitting Panel Built with Waste Glass
The panels were designed as non-load bearing panel prototypes and thought to be used as interior walls to transfer natural light and lower energy costs required to illuminate a room. The panels were manually prepared, positioning the glass inclusions to make sure the glass ran the width of the panels. When they were arranged to the authors satisfaction inside the mold, self-compacting mortar was added all around the flat glass scraps. The mortar mix consisted of a white cementitious high performing binder, dry siliceous sand, potable water, superplasticizer and a de-foamer.
After the panels were constructed, an array of 16 miniaturized illuminance-meters was used to measure the illuminance distribution across the panel. Measurements were taken with and without the panel to form a basis for the data on both light transmission and energy around the testing area. Although the authors noted the best way to measure the light
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transmission of the panels would be to employ the use of a photo-goniometer, they stated this kind of equipment would be used at a future stage of the research. From the equipment they had access to and the tests that were conducted on these panels, it was determined that the glass inclusions were classified as non-reactive under the accelerated Alkali-Silica Reactivity (ASR) test. Furthermore, the light transmission tests resulted in a range of 1.3% to 4.9% of light allowed through the wall (Pagliolico, et al, 2015).
Computer simulations were also carried out to compare the light transmission in a sample room with two sided internal walls. They came up with a similar value of light transmission topping out at 5%. However, the energy demand for lighting inside the room still decreased in a range of 12.7% to 16% because the amount of natural light that was let in due to these panels (Pagliolico, et al, 2015).
2.7 Experimental Study of Transparent concrete (Sabhapathy, 2014)
Many kinds of tests were done in this article to evaluate the effectiveness of a smart transparent concrete. This included a white light test (to determine the amount of light transmission), freezing-thawing test and chloride ion penetration test (to determine long-term durability), and stress elasto-optic effect test (to determine self-sensing properties). In a nut shell, the experiments results show that the smart transparent concrete has good transparency, mechanical, and self-sensing properties. Many of the properties of fiber optics, listed below, contributed to the success of these tests and why they are used in other industries as well (Sabhapathy, 2014).
The life of fiber is longer than copper wire
Handling and installation costs of optical fiber is very nominal
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It is unaffected with electromagnetic interference
Attenuation in optical fiber is lower than coaxial cable or twisted pair.
There is no necessity of additional equipment for protecting against grounding and voltage problems, as it does not radiate energy.
Any antenna or detector cannot detect it, hence it provides signal security
With the help of fiber optics, concrete is no longer the heavy, cold and grey material of the past; it has become beautiful and lively. By research and innovation, newly developed concrete has been created which is more resistant, lighter, white or colored, and now transparent. It can be used to better the architectural appearance of the building and even used where light cannot reach with appropriate intensity. This new kind of building material can integrate the concept of green-energy-savings with the usage of self-sensing properties and promises to be the building material of the future.
(Fathima, 2015)
Figure 2.7: Schematic layout of a molded block with fixed fiber composites within the framework
Transparent concrete works based on Nano-Optics and brings a whole new use to
an industry never thought to need it. Optical fibers pass as much light as tiny slits when they
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are placed directly on top of each other. Hence, optical fibers act like the slits and carry light throughout the concrete, but maintain the compressive strength of normal concrete without the voids or slits weakening the product. On top of this, the manufacturing process of transparent concrete is almost the same as regular concrete. The only difference being that small layers of fibers are infused into the concrete as the fine concrete mix is poured into the mold and on top of each layer of fibers. Fibers and concrete are alternately inserted into molds at intervals of approximately 2 mm to 5mm. This allows the transparent concrete to have good light guiding properties and should be noted that the ratio of optical fiber volume to concrete is proportion to the transmission of light.
2.8 Computational Modeling of Translucent Concrete Panels (Ahuja, et al, 2015)
This study investigated a novel building envelope material that consists of optical fibers embedded in concrete. A computational model of how light and heat is transferred through them was also done to further their research. The fibers in the sample case were used to channel solar radiation into the building to reduce the dependence on artificial lighting, especially during peak time of the day and year. In their research on such material, it was found that the introduction of effective daylight responsive systems can reduce the operating costs of conventional lighting systems by 31% on an annual basis.
Under their literature review, they found four notable steps in the history of translucent concrete that were worth mentioning. In 2001, Hungarian architect Aron Losonczi invented LiTraCon, the first commercially available form of translucent concrete. The University of Detroit Mercy also developed a process to produce translucent panels made of Portland cement, sand and small amounts of chopped fiberglass. These panels,
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which were only 2.5 mm thick at their centers, were it was thin enough to be translucent under direct light. Then, during the 2010 World Expo in Shanghai China, Italy modeled its pavilion out of translucent concrete using approximately 4,000 blocks created by Italecementi and later named them i-light. Another form of translucent concrete featured larger plastic fibers arranged in a grid and was developed by Bill Price of the University of Houston to further his research on translucent concrete. He named his work Pixel Panels and is known for research of translucent concrete rather than commercial manufacturing.
This study utilized the design of the Pixel Panels as a basis for their computation and conclusions drawn below. Their paper presented a geometrical ray-tracing algorithm to simulate light transmission properties of the proposed translucent concrete panel. For simulation purposes, a translucent concrete panel was modeled as a cuboid with dimensions
0.3 x 0.3 x 0.1 meters. The transparency of the translucent concrete panel was varied by changing the volumetric ratio of optical fibers embedded in the concrete. After coming up with the best transparency results with a fiber volumetric ratio of 10.56%, it was then simulated for multiple tilt angles from 0 degrees to 60 degrees (in intervals of 5 degrees) to compute an angle that would transmit maximum light for the whole year. It was then concluded that a tilt angle of 30 degrees transmits the maximum luminous flux.
(Ahuja, et al, 2015)
Figure 2.8: A computational model of transparent concrete panel
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It was also discussed and worth mentioning that as light travels through the core of the fiber optics, it suffers two types of intrinsic losses:
1. Light scattering due to fluctuation in density and composition of material.
2. Light absorption from electronic transitions between the excited and the ground states.
Light absorption leads to heating up of the optical fiber, where as the radiation dissipated via the scattering process is rejected by the optical fiber. In their experiments and because the length of the selected optical fiber was small, the reduction in transmittance ratios across different spectra primarily was due to absorption. They could then conclude that a translucent concrete panel admits more heat than a high-performance window during the year; which is helpful in reducing heating loads during winters, but potentially increases the cooling load for the air conditioning unit of the building during summer months (Ahuja, et al, 2015).
2.9 Development, Testing, and Implementation Strategy of a Translucent Concrete-Based Smart Lane Separator for Increased Traffic Safety (Saleem, et al, 2017)
This paper detailed the development, testing, and real-world application strategy for a new translucent concrete-based lane separator. The proposed device would be embedded into the road surface and can be used for transferring real-time information to the road users. The developed device can transmit colored light by embedding plastic optical fibers in the self-compacting concrete. The self-compacting concrete was prepared based on its increased workability, which allowed it to flow in corners and small areas around the optical fibers placed in the mold. Cube specimens were also cast to check the compressive strength of the
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developed concrete and to evaluate the percentage of light passing through the fibers. The minimum compressive strength requirement was set at 35 MPa to account for large trucks driving over the roadway. The self-compacting concrete was made per the following specifications (Saleem, et al, 2017):
ASTM C150 ordinary Portland cement (Type I was used as a binding material)
Dune sand was used as fine aggregate
Crushed limestone was used as coarse aggregate with a maximum size of 9.5 mm
Polycarboxiate ether-based superplasticizer was added to the mix as 0.5% by volume of cement in order to give the mix the desired workability
The mix constituent contained ordinary Portland cement, fine aggregate, and medium aggregate of a 1, 1.7, and 2 ratios, respectively
The cement content was 370 kg/m3, and water to cement ratio was 0.4
Self-Compacting
Electrical Connection Point Electrical Connection Point Metal Cage Compartment with Refractory
for Sensor Compartment for Lighting Components Base for Uniform Light Dispersion
(Saleem, 2015)
Fig 2.9: Functional description of proposed smart lane separator
Plastic optical fibers (POF) were wound into tendons, of which each tendon was composed of 12 optical fibers wound together into a single piece. The tendons were then
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placed through the predrilled holes of the molds and were secured in place by adhesive glue. It was found that the volume of optical fiber in the concrete was proportional to the light transmitting capability of concrete and would be determined through trial-and-error. Various samples, for compressive strength testing, were prepared by replacing different percentages of fibers to that of concrete. From trial-and-error approach, 3% volume replacement was noted to be the optimal percentage because it resulted in the least loss of strength while giving the desirable translucency. Loading was applied parallel to the POF tendons during testing in order to simulate the real-world application condition. There was found to be an 11.14% reduction in strength, which is considerably lower than that reported in their literature research of approximately 35% (Saleem, et al, 2017). They believe they achieved this by roughing the surface of the POF tendon so the bond between the tendons and concrete could be improved, which leads to the increase in compressive strength. A light transmissibility test was also performed using a light meter, TECPEL 530, to calculate the percentage of light passing through the POF tendons. Keeping in mind the extreme temperatures that the road surface is subjected to during its life cycle, it was also decided to conduct a detailed temperature testing of the cast specimens. It was seen that the specimens were successfully able to sustain high temperatures, and the optical fibers did not melt, even after being exposed to 225C for a long period of time. Because the operational temperature of the road is between 60 and 80C, it can be concluded that the proposed device is suitable for road implementation (Saleem, et al, 2017).
This article is very thought provoking because it takes the idea of translucent concrete and turns it on its side, literally. This idea uses the fiber optics in a vertical setting and in sense places a light behind them to allow illumination from the ground up. Furthermore, the
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article talks of how the fiber optics can withstand weathering and even the weight of vehicles with cyclic loading. It is interesting how different ideas are coming out of the development of translucent concrete, not only for an eye-pleasing architecture but road safety as well.
This idea could be expanded into the idea of LTM too. Perhaps placing emergency lights behind a wall with light transmitting mortar strategically integrated within the joints could be used for fire escapes and lighted pathways or even warning signs in the case of an emergency.
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CHAPTER III
PROBLEM STATEMENT
A multitude of articles and publications regarding translucent concrete, or light transmitting prefabricated concrete blocks, has generated interest by architects since the invention in 2001. Although translucent concrete has emerged as a new construction material, there has been little to no discussion or claims on work towards a light transmitting mortar and the development of it will be the first goal in this experiment. The second goal of this report is to analyze the mechanical performance and physical properties of several different diameters and volumetric ratios of optical fiber to mortar in typical masonry assemblages. Tests used unjacketed end-glow fiber optics that were commercially manufactured and readily available. Two concurrent assessments were made to determine the best diameter and volumetric ratio. The first assessment was done by varying the volumetric ratios, of fiber optics to mortar, from 2.5%, 5%, 7.5%, 10% and 15%. The second assessment used equivalent volumetric ratios, but vary the fiber optics diameter of 1.0 mm,
1.5 mm, 2.0 mm, and 3.0 mm. The selection of the best diameter and volumetric ratio was based on the results of the light transmittance, compressive strength, and shear tests between these two assessments. The mortar design mixture remained unchanged for each fiber volumetric ratio and a control sample of 0% fiber volume ratio was tested to serve as a benchmark for current masonry work and to validate the results.
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CHAPTER IV
EXPERIMENTAL PLAN
For this experiment, four sets of solid prisms consisting of five standard modular clay bricks with type N mortar and fiber optics were assembled and tested. The joint thickness of all prisms was specified to be '/2-inch thick in order to fit the varying sizes and quantities of fiber into the mortar across both tests. Bricks for the prisms were collected from the same stockpile and it was assumed that the bricks used all possessed similar compressive strengths individually. The mortar mix was made using a 3:1 mix of clean, all-purpose sand and typical mortar cement as is specified to prepare Type N mortar. The sand-to-mortar mix ratio will remain the same throughout all batches and verified by weight. The water was supplied by the taps within the laboratory, which provide potable water from the local water authority, Denver Water. Initial water contents were the same by measurement, but water was added on an as needed basis to achieve the desired mortar workability. The prisms were all assembled in the laboratory at the civil engineering department of the University of Colorado Denver and created under normal temperature, atmospheric pressure, and humidity relative to Denver, Colorado in the month of August 2017. Upon completion, all prisms were stored in the same area of the lab and let to cure at room temperature for 14 days prior to testing.
In order to confidently test the mechanical and physical properties as outlined in the problem statement of this report, four specimens from each volumetric ratio were made and tested. The first assessment of a given set is based on the maximum number of fiber optics that could physically fit in a U-inch joint and varying volumetric ratios. This maximum was achieved by laying two rows of the fiber optics per joint. It should be noted that the fiber
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optic diameters and quantities varied in this group to produce volumetric ratios of 2.5%, 5%, 7.5%, 10% and 15%. The second assessment, within this same set, is based on four different sized diameter fiber optics of 1.0 mm, 1.5 mm, 2.0 mm, and 3.0 mm with similar volumetric ratios of about 5%. A control sample without the addition of fiber optics, or volumetric ratio of 0%, was also built to serve as a benchmark for the results.
A set of three-brick prisms were then made to test the shear strength and evaluate the location of failure when lateral forces may be applied to the masonry assemblages. These prisms were created in the same way as above, but only used three bricks so they could be turned on their side and placed in a 3-point bending setup. This set of prisms was created based solely on varying volumetric ratios and the maximum amount of fiber optics that could be placed in a given joint because it was thought the best chance of failure due to the fiber optics would be achieved when the most fibers optics possible were put into a joint.
Figure 4.0: The making of mortar cubes
Mortar cubes, without fiber optics, were also cast from each batch throughout the process to verify that the mortars compressive strength remained relatively similar over each
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set of prisms. This was done by placing mortar within a 2 x 2 x 2 Vi opening made from laying four bricks together as illustrated in Figure 4.0. To replicate water absorption that would be expected to occur if the mortar were used in prisms (or in the field), paper towels were used in lieu of any other bond release agent to facilitate the removal of the cubes from the brick forms.
4.1 Properties of Light Transmitting Mortar
4.1.1 Fiber Volume Ratio
The components that make up LTM consists simply of a mortar mix and optical fibers. This idea is achieved by laying optical fibers into the mortar mix so that the fiber optics reach from one side of the brick to the other. This allows light to be transmitted from one side of a wall to the other through the fiber optics. Commercially developed fiber optics can come in a variety of types, but typically are made of either plastics and glass. The basis for many of the tests in this experiment are based on volumetric ratios of fiber to an individual joint. This volume ratio, Vf, is found by taking the total volume of fibers and dividing it by the overall volume of the composite mortar.
Vf = (vf/vc) x 100%
Where:
V/= Volume Ratio of Fibers
Vf = volume of fibers
vc = volume of composite mortar
The fiber optic volumetric ratio for LTM will be used throughout the experiment as the controllable variable. This will not only pertain to the ability of the mortar to transmit
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light, but also to test physical qualities like compressive strength as well. It should be noted that several manufacturers have stated that the addition of the plastic or glass optical fibers has also increased the tensile and flexural capacity of concrete products, but these properties are beyond the scope of this report and were not tested on the LTM (Illston, 2010). The first assessment of prisms was sought to test varying volumetric ratios to find the effects of increasing the amount of fiber optics within the mortar. The volumetric ratios of fiber to mortar were selected based on limiting spacing requirements for the fibers within a V2 joint. It should be noted that to achieve the larger volumetric ratios, one must increase the diameter of the fiber optics as well as the quantity of them. The second assessment of prisms were all specified to have equal volumetric ratios in order to find differences in increasing diameters of the fiber optics. The calculations of the volumetric ratios and the number of fiber optic pieces are show in the table below.
Table 4.1.1: Volumetric Ratio Design Table
Cross Sectional Area 8t Number of Pieces Needed to Cut (Varying CSA)
Mortar Only 1.0 mm: 1.0 mm: 1.5 mm: 2.0 mm: 3.0 mm:
(# of pieces/Joint) I 0 75 150 100 75 50
Area per Single Fiber 0.00 mm2 0.73 mm2 0.73 mm2 1.77 mm2 3.14 mm2 7.07 mm2
Area of Fiber per Joint 0.00 mm2 58.88 mm2 117.75 mm2 176.63 mm2 235.50 mm2 353.25 mm2
Area of 1/2" joint 2413 mm2
Area Ratio 0.0014 2.4314 4.Sly. 7.3014 3.7314 14.6014
(Joints/Prism) 4
(# of Specimens) 4
# of Pieces Needed - 1200 2.400 1.600 1.200 800

Cross Sectional Area 8t Number of Pieces Needed to Cut (Equivilant CSA)
(# of pieces/Joint) Mortar Only 1.0 mm: 1.5 mm: 2.0 mm: 3.0 mm:
0 150 70 40 20
Area per Single Fiber 0.00 mm2 0.73 mm2 1.77 mm2 3.14 mm2 7.07 mm2
Area of Fiber per Joint 0.00 mm2 117.75 mm2 123.64 mm2 125.60 mm2 141.30 mm2
Area of 1/2" joint 2413 mm2
Area Ratio 0.00:4 4.Sly. 5.1114 5.1314 5.8414
(Joints/Prism) 4
(# of Specimens) 4
# of Pieces Needed - 2.400 1.120 640 320

1.0 mm: 1.5 mm: 2.0 mm: 3.0 mm:
Feet per Spool 4.320 ft 2.236 ft 1.148 ft 432 ft
Possible # of Pieces per Spool 11.808 ea 5.510 ea 2,755 ea 1,181 ea
Feet left on Spool 2.420 ft 1.163 ft 381 ft 25 ft
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4.1.2 Optical Fibers
Fibers can be used in either multifilament or monofilament arrays. Multifilament fibers will consist of a bundle or grouping of fibers where individual filaments may or may not be in contact with the mortar mix. Some designers will use this characteristic of bundles to allow the bundles to remain flexible in the core of the grouping where fibers are not bonded with the mortar, adding additional ductility to the reinforcing fibers. Monofilament fibers consist of a single fiber allowed to fully bond with the surrounding mix. For the purposes of this study we will be examining the behavior of monofilament plastic polymer fibers cut to a length of 5 inches and placed within the mortar joint of the prism. In order to explain the basic principles that allow these small fibers to transmit light so efficiently we must first understand the components of a typical light guiding optical fiber. The main body of the fiber is made up of the core and is typically manufactured by extrusion of a silica glass or polyethylene melted into a liquid form which is then pulled into the desired diameter. These fibers are then dipped into a cladding mixture which will have a lower refractive index than the inner core. This allows incandescent light waves on the inner core to propagate along the length of the fiber continuously reflecting against the cladding. This leads to total internal reflection which allows the light to travel relatively large distances with little to no power loss. A general example of the entrance and reflectance of light in an optical fiber can be seen in Figure 4.1.2.
Some typical light guiding fiber optics can allow light to travel over 1 km with approximately 3.6% power loss. Most people see this application in everyday fiber optic cable television transmission. For the application of LTM, we are less concerned with the amount of light loss as the transverse distances traveled are relatively small in comparison.
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The numerical aperture of a fiber is a value ranging from 0 to 1 and is used to quantify the incident angle of light able to enter the face of the core. The cone traced out by this acceptance angle is known as the acceptance cone.
(https://en.wikipedia.0rg/wiki/File:Optical-fibre.png) Figure 4.1.2: Optical Fiber Principles
Light entering the core within the acceptance cone propagates the length of the fiber, whereas light entering the core at an angle greater than the acceptance angle is only guided along a very short distance along the fiber where it continuously reflects and eventually dissipates. A refractive index describes the ability of the material in which the light is traveling to propagate incandescent light. Cladding will have a lower refractive index than the core it encloses which allows light to efficiently be reflected through the core. If the cladding had a larger refractive index the light traveling through the core would pass through the cladding and lead to less efficient light transfer. This study used Polymethyl-Methacrylate Resin fibers without a cladding. The use of a cladding would provide for more efficient optical fibers, but for the relatively short transverse distances of the width of bricks used in this experiment unsheathed optical fibers were selected.
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4.1.3 Mortar Design Mixture
Mortar is a workable paste used to bind building blocks such as stones, bricks, and concrete masonry units together. Cement mortar becomes hard when it cures, resulting in a rigid aggregate structure; however the mortar is intended to be weaker than the building blocks and can be a sacrificial element in the masonry. Mortars are typically made from a mixture of sand, a binder or cement, and water.
The ASTM Standard C270 (Mortar for Unit Masonry) provides the basis for specifying cement-lime mortars. This specification provides the basis for five different mortar types (Type M, S, N, O, and K) depending on the strength of mortar needed for an application. (These type letters are taken from the alternate letters of the words "MaSoN wOrK"). Type M mortar is the strongest, and Type K the weakest. The Appendix of ASTM C270 provides a reference to which mortar type should be used in some general applications and an adapted version of this list is shown in Table 4.1.3.
Table 4.1.3: Mortar type for some general applications
Location Use Mortar Type
Recommended Alternative
Exterior, above grade Load-Bearing Wall N S or M
Non-Load Bearing Wall 0 N or S
Parapet Wall N S
Exterior, at or below grade Foundation Wall or Retaining Wall S N or M
Pavements, Walks or Patios S N or M
Interior Load-Bearing Wall N S or M
Non-Load Bearing Partitions 0 N
From the table above, and availability at a local hardware store, Type N mortar was selected for this experiment as a realistic application for a wall with LTM. For a basic mortar mix, it was prescribed to mix essentially three parts of sand for every one part of cement
38


used. That means if mixing up a whole 70-pound bag of cement, the prescribed amount will use three times that of sand and will result in a large batch of mortar mix. Due to the time it takes to individually lay the fiber optics into the joints, only 6 pounds of cement and 18 pounds of sand where mixed per batch. Although it has been said that the measurement doesnt need to be precise as a baking recipe, it was kept equivalent from batch to batch for the integrity of the experiment. At most work sites, when mixing large amounts, the amount of sand is usually given in "shovels full" per bag of mortar mix, which usually works out to somewhere between 15 and 18 scoops, depending on how large the shovel scoops are.
4.2 Manufacturing Methods
It is essential that methods of creating test prisms and the tests themselves remain equivalent as possible to limit eccentricities and anomalies that could be found later. It is also vital in the experimental process that all variables are controllable and only one variable is changed at a time. This way it is clear what is affecting the results. In saying that, great measures were taken to make sure the only variable in this experiment that was changed was the volumetric ratio of fiber optics to mortar within each joint. Further research shall be done to test other variables such as the direction or spacing of the fiber optics. A freeze-thaw test or heat testing could also be done in the future to test the durability of the fiber optics in harsh weather conditions. For this thesis, one person mixed every batch of mortar, laid each fiber optic individually, and placed every brick across all specimens to limit the number of uncontrollable variables. The bricks were obtained from the same stock pile and the fiber optics were ordered from the same distributor. Each set of prisms were created one-after-another on individual days, but allowed exactly the same amount of time to cure before testing them. Meaning if the first set was created on a Monday, it was tested two weeks later
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on a Monday around the same time. The testing apparatuses and data acquisition programs were also the same amongst every test and loaded by the same individual. The following manufacturing methods were closely followed to produce the LTM prisms studied in this report and attention to every detail was well documented.
4.2.1 Setup and Preparation
The fiber optics came in rolls of 4,920 feet for the 1.0 mm diameter fiber; 2,296 feet for the 1.5 mm diameter fiber; 1,148 feet for the 2.0 mm diameter fiber; and 492 feet for the 3.0 mm diameter fiber. These were needed to be cut down to lengths of 5 inches to allow the fiber optics to extend past the width of the brick. The calculation of number of fiber optics needed were shown in Table 4.1.1 of the previous section and tracked as some pieces were cut by hand and others were sent off to be cut commercially.
After a few trial and error attempts to cut this many pieces by hand, the services of Allcable, Inc. was enlisted to have the fiber optics cut mechanically by a large machine seen in Figure 4.2.1. They were able to take the spools and load them into large machines that would then send the fiber optics through rollers to measure out exactly 5 inches and simultaneously slice the pieces into a hopper. This dramatically reduced the amount of time it took to do by hand and actually helped straighten the pieces a bit from the inherent curve that was created from being on the spools. The only other step that was done by hand was separating the fibers into bags with the quantities specified by the volumetric ratio calculations; this way one bag could be used per joint as the prisms were built.
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Figure 4.2.1: Machine at Allcable, Inc. to cut fiber to length
It is noted that for future tests a manufacturer will be found to produce a mesh of fiber optics with the same spacing and lengths in order to reduce even more variables. Not much time was spent looking for a manufacturer to cut the pieces to length because it was thought cutting them by hand would not be an issue. This proved to be the first major road block of the manufacturing process, but opened up new ideas for future testing and how enlisting the services of an established manufacturer can help in many ways.
4.2.2 Building the Prisms
Once the fiber optics were put into individual bags, it was easy to make sure the exact number of fibers specified were placed inside each joint. To build an individual test prism, it
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is best to set everything up in a smart workable area, meaning all the bricks for each prism are easily accessible and the bags of fiber optics for the 4 joints are ready to be used. A batch a mortar shall be mixed per the specifications discussed in the previous section and kept moist for good workability. To make test prisms, the steps below were followed:
Figure 4.2.2-1: Building a typical mortar joint with fiber optics
1) Make sure the first brick is level (it will be crucial for testing that the bottom
surface is parallel to the top surface)
2) Then a thin layer of mortar should be placed and troweled over the top of the first
brick (make sure the top part of the brick is completely covered)
3) A layer of fiber optics can now be laid on top of the thin layer of mortar
4) Trowel another thin layer of mortar on top of the fiber optics
5) Place the next brick of this prism on top of the composite bed of mortar
6) Tap the brick down with the butt of the trowel to sit in the mortar
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7) Take measurements to make sure the joint thickness is V2 inch throughout as
specified (It is also crucial to make sure the top brick is still level and aligned with the brick below)
Figure 4.2.2-1: Keeping it consistent
8) Repeat steps 1-7 until a 5-brick prism is complete
9) Once the prism is complete, label it with the date created, the diameter and the
number of fiber optics used in said prism
10) Set the prism in a secure area of the lab to let cure.
Once a prism was complete for a given diameter of fiber optics, the process was repeated for the next diameter of fiber optics before the same specimen was repeated. A set of specimens consisted of the following diameter and quantities of fiber optics per joint:
Mortar only
3.0 mm diameter with 20 fibers
2.0 mm diameter with 40 fibers
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1.5 mm diameter with 70 fibers
1.0 mm diameter with 150 fibers
3.0 mm diameter with 50 fibers
2.0 mm diameter with 75 fibers
1.5 mm diameter with 100 fibers
1.0 mm diameter with 75 fibers
It is noted that the mortar only and 1.0 mm diameter with 150 fibers prisms were only done once per set, but the data was used for both assessments. Three batches of mortar were needed to complete each set and a complete set was done by one individual in about 3 to 4 hours straight through. Four sets of specimens were constructed the same way on different days to limit the variables within a set. A set of 3-brick prisms were created in the same way for shear testing.
4.2.3 Grinding and Polishing
After a week of letting the prisms cure, the mortar was strong enough to come back and grind off the excess fiber and mortar. This was done to give the wall a clean and flush look that would normally be seen with brick masonry, but also to make sure that the fiber optics reached completely from one side to the other and the ends were not covered with dry mortar. If fiber optics were exactly the width of the brick, it is possible that the mortar could cover the ends of the fiber, thus not allowing light to transmit through the wall. Grinding or flush cutting the fiber optics also allowed for a new smooth end to have a better acceptance cone of the source light. Grinding was done with a typical 4 angle grinder with a masonry disk and seen in Figure 4.2.3a and 4.2.3b:
44


a) b) c)
Figure 4.2.3: Grinding & Polishing
During testing, it was thought that using a heat gun would melt the ends of the fiber optics and polish them over to improve light transmission as well. Testing was done before and after the heat gun and although to the naked eye it didnt make much of a difference, the results outlined in further sections show it does make an improvement of the measured lumens transmitted through the mortar. The heat gun was turned on high and run along the joint at about a rate of 1 inch per 2-3 seconds as shown in figure 4.2.3c. It was noticed that when using the heat gun, the fibers start to melt and pulled back into the voids of the mortar. However, because the solid mortar acted as a sort of cladding it appeared that it was not possible to over melt the fiber optics at the rate used in this experiment.
4.3 Testing Methods
The prisms were all tested for light transmission, compression strength, and the whereabouts of shear failure. Light transmitting data as well as load to deflection data was collected and analyzed in subsequent sections.
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4.3.1 Light Transmittance Test
The light transmittance test will measure the illuminance of light transmitted through the LTM by way of the plastic optical fibers. Illuminance measures the luminous flux per unit area. In this report all measurements of illuminance will be in Lux units. Luminous flux is the unit of measurement used in lighting photometry that describes the amount of power produced by a lighting source. Prior to testing, the samples were cleaned to remove any debris left over from the grinding process. The light transmittance test is a nondestructive test and as such, the specimens from this test were re-used for compression tests. The light test was carried out after 7 days of curing and the excess fiber and mortar was ground smooth. A second light transmittance test was conducted after the use of a heat gun to melt the ends of the fiber optics, essentially polishing them to theoretically allow a larger cone of light acceptance.
Light Source
Figure 4.3.1-1: Light Transmittance Test Box Diagram
To test the LTM, each test prism was placed inside a box that measures 8 wide by 13 tall by 28 deep as seen in Figure 4.3.1. One side of the box was left open, so the prisms could be loaded in the middle and a halogen light source can be placed exactly 12 inches
46


away from the face of the test prism. The other side of the box was enclosed as to not allow any external light inside, but had circular cut outs in order to place a light meter at predetermined heights. A light meter was used on both sides of the box to measure illuminance levels. On the light source side of the box, measurements were taken at 7 (from the bottom of the box), but directly in front of the masonry prism. On the output side, measurements were taken at 2.5, 7 and 11.5 from the bottom but at the end of the box which was exactly 12 inches from the back face of the masonry prism.
Figure 4.3.1-2: Light Transmittance Test Box
The equation for calculating transmittance can be found below and results are to be tabulated in the results section of this report:
T = {IHo) x 100
Where:
T = Transmittance percentage I = Transmitted Illuminance Io = Source Illuminance
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4.3.2 Compressive Strength Test
Compression testing of the prisms was performed after a 14-day curing time. The prism tests were performed using a 220-kip capacity, Material Testing System test frame in the UCD Structures Lab with a rotating spherical head that allowed for uniform loading even if the ends of the prisms were slightly out of parallel. The procedure began with installing the prisms into the MTS testing machine to be compressed at a constant rate of 0.003-inches per second by a hydraulic ram. The samples were loaded until failure occurred. During the test, the load and displacement data of the displaced plate was recorded using a computer-based data acquisition system to calculate the compressive strength. Subsequent to the testing of the final prism, a single brick was also compression tested, which provided for a baseline strength of the units.
Figure 4.3.2: Testing the Compression Strength of a Prism
Because the bricks were obtained from an un-labeled stockpile that was stored just outside of the CU Denver, Civil Engineering Testing Laboratory, their compressive strengths were unknown. However, as will be indicated in the results section of this report, the tested
48


compressive strength of a single brick was approximately 4300 psi. According to the TMS-602 (Masonry Standards Joint Committee, 2013), a prescriptive masonry strength can be derived and should be approximately 1500 psi for a unit strength of 4150 psi and Type N mortar. This is true provided that mortar joint widths do not exceed 5/8 inch, as was the case for all of the test prisms.
The capacity of masonry assemblages is dependent on the masonry compressive strength, fm, defined as the maximum compressive force resisted per unit of net cross-sectional area of masonry (Masonry Standards Joint Committee, 2013). This fundamental material property for a masonry assemblage can be determined by an empirical method where compressive strength is expressed as a function of the material properties of the individual components of the assembly (units, mortar and grout). Additionally, the compressive strength of masonry can be determined through testing of masonry prisms in accordance with ASTM C1314, (Standard Test Method for Constructing and Testing Masonry Prisms Used to Determine Compliance with Specified Compressive Strength of Masonry).
In addition to the relevant data of comparative compressive strengths of the various prisms, and those compressive strengths relative to that which is prescribed in TMS-602, given the number of data points, it was also possible to derive an approximate modulus of elasticity of the prisms. It is prescribed in TMS-602 that the modulus of elasticity of clay masonry assemblages is 700 times fm. If the prescriptive fm equals 1500 psi and is assumed to be valid, then the modulus of elasticity would be approximately 1050 ksi. The slope of the stress/strain curves was approximated for each prism using data points at which
49


the curves were most linear and compared to the prescribed elasticity, based upon the tested fm value.
Like the brick prisms, the mortar cubes were allowed to cure for 14 days in the laboratory at normal humidity levels. The mortar cubes were then compression tested using a 20-kip rated MTS test frame. The cubes were compressed at a constant rate of 0.001-inches per second until failure.
4.3.3 Shear Test
There are no proper code specifications for testing shear bond strength of masonry assemblages. Hence, a setup was made as shown in Figure 4.3.3-1 particularly to test the shear bond strength of the three-brick prisms. Since the specimen should be inserted into the testing machine in such a manner that the load acts parallel to the mortar joint, the test prism was turned on its side and compression tested in a 3-point bending setup. This was done using a 20-kip rated MTS test frame after a 14 day curing period as well. A small steel plate, roughly the size of the end of a single brick, was placed under a spherical head on the MTS ram in order to move the point of load application to a point as near the joint as possible in order to minimize the bending moment. The center brick was then compressed by this steel plate and piston at a constant rate of 0.001-inches per second as the outer bricks were simply supported, allowing failure to occur in a slip format.
It was thought that by laying the fiber optics parallel to only one axis and basically side-by-side along the whole length of the joint, a slip plane would be created inside the mortar joint and along the fiber optics. However, as it will be reported in the results section, shear failure occurred along the bond of the brick and the composite mortar joint.
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Figure 4.3.3-1: Shear Test Setup
The bond shear strength was determined as the arithmetic mean of all successful individual tests. A test was regarded as not successful and discarded if the brick unit crushed during the test. The bond shear strength t0 was determined in the absence of normal stresses perpendicular to the mortar joint and by the following equation:
To = F / (A1 + A2)
Where:
To = the bond shear strength
F = the maximum force applied by the test machine A1 = the area of the upper joint A2 = the area of the lower joint
The characteristic failure patterns shown in Figure 4.3.3-2 were also recorded keeping in mind that intermediate patterns are possible. It is noted that the failure of a typical masonry assemblage usually occurs in the unit/mortar interface, being distributed either on one or on two sides of the unit (Rilem, 1996). This type of failure is illustrated as failure pattern (a) in the figure below. It was thought that by adding a row of fiber optics inside the mortar, it would cause a failure pattern (b) as illustrated in the figure below. This would
51


mean that the addition of fiber optics could cause a critical shear failure of LTM masonry assemblages not typically found in masonry assemblages without fiber optics. Failure pattern (c) illustrated in the figure below demonstrates an extreme bond strength between the mortar and brick unit. This typically indicates an inferior strength of a brick unit itself and the measured value is considered the shear strength of the brick, not the bond shear strength.
Failure pattern (b) Failure pattern (c)
Failure of mortar only Failure of the unit
(Rilem, 1996)
Figure 4.3.3-2: Shear Failure Patterns
The failure patterns were visually inspected throughout all shear test specimens and documents in the results section of this report. These failure patterns proved to be the main purpose of the shear test because bond shear strength can vary greatly and without reason from test to test. Although the bond shear strength was calculated and tabulated in the results section, pictures were also taken and presented in the results section to be compared to the failure patterns in Figure 4.3.3-2.
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CHAPTER V
RESULTS
5.1 Light Transmittances
Although the transmitted measurements of the light transmittance tests were low by comparison to the source, the effect was pronounced when seen by the naked eye. Examples of the halogen light beam striking the faces of the prism can be seen in Figure 5.1-la and the light transmittance through the fiber optics on the output side can be seen in Figure 5.1-lb. Even a flash light from a basic smart phone illuminated the fiber optics within the mortar joints and could be seen in the daylight. However, the idea of light transmitting mortar is expected to achieve its full effect in the night or in low light settings. In stating this, the results of the measurements taken did behave as expected in the sense that the higher the fiber volumetric ratio, the higher the light transmittance.
a) b)
Figure 5.1-1: Inside the Light Test Box
When the volumetric ratio was kept equivalent at about 5% then the best light
transmittance on average was 42 lux from the 2.0 mm diameter fiber optics. A summary of
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the data collected can be found in Table 5.1: Light Transmittance Test Results. This data can vary due to the grinding and polishing procedures used during the fabrication of the prisms and is expressed as the averages over 4 sets of tests. A rougher finished surface causes light to be transmitted in a diffuse pattern which is less efficient than a clean smooth finish and in turn could decrease the transmittance levels. It should also be noted that the fibers were laid
individually and the curvature from the spool could have changed the angle at which the light was transmitted, effecting the readings at the point the light meter was placed.
Table 5.1: Light Transmittance Test Results
Increasing Fiber Volumetric Ratio (Based on max# of Fibers Optics to Fit into Joint)
Mortar Onlv 1.0 mm: 1.0 mm: 1.5 mm: 2.0 mm: 3.0 mm:
(# of pieces/Joint) o 150 100 75 50
Number of Fibers / Row 0 75 75 50 37 25
Area Ratio Mortar Only 2.43% 4.87% I 7.30% 9.73% 14.60%
Before Heat Gun
Avg. Amount of Light Output 1 lx 3 lx 4 lx 7 lx 18 lx 31 lx
Amount of light Source 35,300 lx 34,825 lx 35,950 lx 34,550 lx 35,350 lx 35,100 lx
Ratio of light Through Prism Mortar Only 0.010% 0.011% 0.020% 0.051% 0.089%
After Heat Gun
Avg. Amount of Light Output 1 lx 11 lx 14 lx 24 lx 45 lx 74 lx
Amount of light Source 34,725 lx 34,650 lx 34,425 lx 34,250 lx 33,775 lx 34,375 lx
Ratio of light Through Prism Mortar Only 0.031% 0.042% 0.069% 0.134% 0.215%
| Inc, of Light After Heat Gun
OK
216%
264%
247%
164%
142%
Mortar Only 1.0 mm: 1.5 mm: 2.0 mm: 3.0 mm:
(# of pieces/Joint) l 15D 70 4D 20
Number of Fibers / Row ol 75 70 40 20
Area Ratio 0.00% 4.87% 5.11% 5.19% 5.84%
Equivilant Fiber Volumetric Ratio
Avg. Amount of Light Output 1 lx 4 lx 6 lx 11 lx 11 lx
Amount of light Source 35,300 lx 35,950 lx 36,125 lx 36,650 lx 34,900 lx
Ratio of light Through Prism 0.003% 0.011% 0.017% 0.031% 0.030%
Avg. Amount of Light Output 1 lx 14 lx 22 lx 42 lx 26 lx
Amount of light Source 34,725 lx 34,425 lx 34,825 lx 34,950 lx 34,825 lx
Ratio of light Through Prism 0.003% 0.042% 0.063% 0.119% 0.074%
|lnc. of Light After Heat Gun
0%
284%
271%
284%
147%
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The most interesting thing that the testing revealed was that after applying the heat gun, transmittance increased anywhere from 142% to 284% with the smaller diameter fibers showing the most benefit from the heat gun. A graph of the increasing transmittance vs. the fiber volume ratio can be found in Figure 5.1-2 and a second graph of varying the diameter of
the fiber optics vs. the light transmittance ratio can be found in Figure 5.1-3.
Fiber Optic Volumetric Ratio vs. Light Transmittance
I Before Heat Gun H After Heat Gun
0.215%
0.134%
0.069% I 0.08
0.031% -042% M 0.05 ^ I
o.oi0 o.oj o.o^p
0.250%
0.200%
0.150%
0.100%
0.050%
0.000%
tU3
D
O
Mortar Only 2.43% 4.87% 7.30% 9.73% 14.60%
Ratio of Fiber optics to Mortar in Joint (by Area)
*Diameter of Fiber Optics Vary
Figure 5.1-2: Light Transmittance vs. Fiber Volumetric Ratio
Fiber Optic Diameter (Equal Volumetric Ratio) vs Light Transmittance
Mortar Only 1.0 mm: 1.5 mm: 2.0 mm: 3.0 mm:
Diameter of Fiber Optics (Equal CSA)
*Fiber Optics Cross Sectional Area is about 5% of Joint
Figure 5.1-3: Light Transmittance vs. Fiber Optic Diameter
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5.2 Compressive Strength
A summary of the data collected can be found in Table 5.2: Compressive Strength Test Results. This data can vary slightly due to the inexperience of masonry work and fabrication of the prisms, but all prisms were created by the same person and believed to be made as equivalents.
Table 5.2: Compressive Strength Test Results
Compression Strength (Varying Volumetric Ratio)
(# of pieces/Joint) Mortar Only 1.0 mm: 1.0 mm: 1.5 mm: 2.0 mm: 3.0 mm:
0 75 150 100 75 50
Volumetric Ratio O.OOX 2.43 V: 4.87 V: 7.30 V: 3.73V: 14.60 V:
Specimen 1 50 kips 56 kips 63 kips 66 kips 64 kips 63 kips
Specimen 2 52 kips 71 kips 55 kips 61 kips 61 kips 70 kips
Specimen 3 54 kips 68 kips 72 kips 68 kips 72 kips 77 kips
Specimen 4 65 kips 83 kips 73 kips 32 kips 78 kips 81 kips
Aug. Comp. Strength 55 kips 63 kips 68 kips 72 kips 63 kips 74 kips

Compression Strength (Eguiuilant Volumetric Ratio)
Mortar Only 1.0 mm: 1.5 mm: 2.0 mm: 3.0 mm:
(4 of pieces/Joint) 0 150 70 40 20
Volumetric Ratio o.oov: 4.87 V: 5.11V: 5.13:4 5.84 V:
Specimen 1 50 kips 63 kips 71 kips 73 kips 73 kips
Specimen 2 52 kips 55 kips 68 kips 65 kips 53 kips
Specimen 3 54 kips 72 kips 84 kips 63 kips 65 kips
Specimen 4 65 kips 73 kips SO kips 68 kips 74 kips
Aug. Comp. Strength 55 kips 68 kips 76 kips 63 kips 63 kips
A graph of the compressive strength vs. the fiber volume ratio can be found in Figure 5.2-1 and a second graph of the compressive strength vs. the fiber weight ratio can be found in Figure 5.2-2. These graphs are based on the averages over four sets of testing. It appears if any ratio of fiber optic is added to a mortar joint, it substantially increases the maximum compression strength of the prism.
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Fiber Optic Volumetric Ratio vs Compressive Strength
80.00 70.00 't/T
60.00 Q. (D
50.00 u l_ O Ll_
40.00 C _o 'cn
30.00 20.00 o u x;
10.00 0.00 ro
Ratio of Fiber Optics to Mortar in Joint (by Volume) *Diameter of Fiber Optics Vary
Figure 5.2-1: Compressive Strength vs. Fiber Volumetric Ratio
Weight Ratio vs Compressive Strength
Mortar Only 1.12% 2.39% 2.84% 4.04% 6.11%
80.00
70.00
60.00
50.00
40.00
30.00
20.00 10.00 0.00
Q.
01
Q.
O
U
X
Ratio of Fiber Optics to Mortar in Joint (by Weight) Averaged over 4 tests
Figure 5.2-2: Compressive Strength vs. Fiber Weight Ratio
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A graph of the assessment with equal fiber volumetric ratios, but varying the diameter of the fiber optics vs. the maximum compressive strength can be found in Figure 5.2-3. This graph was used to determine the best diameter of fiber optics that should be used based on
the maximum compressive strength.
Fiber Optic Diameter vs Compressive Strength
(Fiber Optics Volumetric Ratio is about 5% of Joint)
80.00
70.00
'J/l'
60.00 2
O
50.00 £
c
_o
40.00 8 a)
i_
Q.
30.00 I
U
X
ro
20.00 5
10.00 0.00
Mortar Only 1.0 mm: 1.5 mm: 2.0 mm: 3.0 mm:
Diameter of Fiber Optics (Equal Volumetric Ratio)
Figure 5.2-3: Compressive Strength vs. Fiber Optic Diameter
76
68 69 69
55 1

5.3 Shear Strength
The results of the shear tests seem to have little variation depending on whether fiber optics were added to the joint or not. The failure pattern of each test prism can be seen in Figure 5.3-1 and all categorized as failure pattern (a) from Figure 4.3.3-2 in the previous section. All tests were categorized as this because the failure was along the bond between the brick and mortar, even though a couple cracks went directly through the mortar and continued along the bond line. In order to achieve failure pattern (b) and support the theory
58


that the addition of fiber optics had anything to do with the failure, the crack would need to propagate entirely inside the mortar joint and not along the bond line.
a) No Fiber Optics b) 1mm Dia. Fiber Optics c) 1.5mm Dia. Fiber Optics
d) 1.5 Dia. Fiber Optics e) 2mm Dia. Fiber Optics f) 3mm Dia. Fiber Optics Figure 5.3-1: Results of Shear Failure
The results of the shear strength test and calculations of the bond shear strength are tabulated in Table 5.3 and shown in Figure 5.3-2. The values of specimen 1 were not included in the graph of Figure 5.3-2 because they came from a batch of mortar mix that had less water content and the joints measured to be 5/8 instead of the V2 specified. The prisms
59


created in Specimen 1 were the very first set created and was originally used more to determine the maximum number of fiber optics that could fit in a joint. The subsequent prism sets and batches of mortar were believed to have a more refined masonry work as the learning process went along. However, the prisms from specimen 1 were also shown to fail in the same pattern and the results were believed to be applicable and worth showing.
Table 5.3: Shear Strength Results
Shear Strength (Varying CSA)
Mortar Only 1.0 mm: 1.0 mm: 1.5 mm: 2.0 mm: 3.0 mm:
(# of pieces/Joint) 0| 751 | 150 I 1001 751 501
Volumetric Ratio Mortar Only 2.43;-: 4.67 V: 7.30 V: 3.73V: 14.60 V:
Specimen 1 2.93 kips kips 0.37 kips 2.08 kips kips kips
Specimen 2 3.88 kips 4.68 kips kips 4.65 kips 3.00 kips 4.65 kips
Average Maw Shear Strength 3.41 kips 4.68 kips 0.37 kips 3.36 kips 3.00 kips 4.65 kips
Area of top joint 27.64
Area of bottom joint 27.64
Bond Shear Strength 61.61 psi 84.84 psi 17.51 ££! 60.85 psi 54.27 psi 84.12 psi
Bond Shear Strength vs. Fiber Volumetric Ratio
'cn
Q.
90
80
70
60
50
40
30
20
10
0

Mortar Only 2.43% 7.30% 9.73% 14.60%
Volumetric ratio, %
Figure 5.3-2: Bond Shear Strength vs. Fiber Volumetric Ratio
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CHAPTER VI
CONCLUSION
Light Transmitting Mortar is now an exciting and new innovation for the masonry industry. LTM doesnt only create a completely new architectural lighting effect, that will undoubtedly bring life to the idea of an old brick and mortar wall, but it has been shown to increase the structural properties to the overall assemblage as well. This added benefit might actually bring light to new possibilities of masonry construction and take brick walls out of being a just a veneer as they have seemed to become. A summary and conclusions from this experiment, as well as a few recommendations for future research, can be found below for each section of the report.
6.1 Manufacturing Methods
The fabrication process was extremely laborious and time consuming when completed by hand, but there are a couple ideas that could address this issue. A fiber optic Light Transmitting Mesh could be created in standard sizes or rolls to allow masons to simply lay directly into the mortar as they carry on with their normal work. An automated process to straighten, cut, lay these pieces side by side (with about 2mm between each piece) and glue them together would be a wise investment in terms of time savings and quality control.
The hardest thing to deal with during this experiment was by far the slight curvature inherent in the 5-inch pieces. This was because the amounts of optical fibers ordered were delivered on large spools. Due to the fact that the manufacturer wound them onto spools as the plastic was extruded, it left a permanent curvature in the fibers that was still seen during the process of pulling them off the spool and cutting them to such short lengths. If a straight
61


fiber was to be used, it would not only produce a better arrangement along the length of the brick, but would also create a more uniform line of light transmittance on the other side of the wall.
The grinding process used a normal 4 angle grinder with a masonry disk that had no problem cutting off the excess fibers and mortar through most sized diameters of the fiber optics. However, the 3.0 mm diameter fiber was quite a bit more difficult than any other size because it made the grinder jump from fiber to fiber as it cut through each one and caused marks to be left on the brick units. Any size smaller than the 3.0 mm diameter fiber optics cut extremely smooth with the masonry disc.
6.2 Light Transmittance
The light transmitting mortar performed as expected during the light transmittance tests with an increase in light transmittance as the fiber volumetric ratio increased. Further improvements could be made by using higher grade optical fibers and a better way to polish the ends to reduce the number of imperfections on the exposed faces of the fibers. Although it was a little surprising the light meter gave as low values of light transmittance as was recorded, tests were double checked and spot checked on different days to verify the results. It was only surprising because the effect seen by the naked eye was quite a bit better than expected. Even before the ends were ground smooth and with excess mortar partially covering the ends, visible light was seen and gave a twinkling effect. This leads me to the conclusion that even during weathering and harsh outdoor conditions, LTM will continue to give the desired effect over long periods of time. Although it was not tested during this
62


report, it is believed that the fiber optic elements would stand up to cleaning and power washing procedures just as well as brick and mortar does on current walls.
Even though it was demonstrated that increasing the fiber volumetric ratio increased the light transmittance, it was also shown that simply increasing the quantity of the same diameter fiber optics did not necessarily increase the light transmittance linearly. Since this is thought to be true, there does not seem to be any benefit in packing in large quantities of fiber optics into a single joint. When equal volumetric ratios were tested based solely on varying the diameter of the fiber optics, it appears that the best selection to be used in a final product would be the 2.0 mm diameter fiber optic. This conclusion is based solely on the light transmittance test.
6.3 Compressive Strength
The results from the compressive strength tests showed that the addition of any size or quantity of fiber into a mortar joint substantially increases the compressive strength of the overall assemblage. This is thought to be true because the added tensile strength of fiber. During a compression test of the masonry assemblages, failure occurs due to the development of tensile stress in the masonry unit or bricks. Bricks and mortar will sustain both axial and transverse deformation when compressed. Poissans Ratio (v) is defined as the ratio of transverse deformation, or strain, to axial deformation, and is higher for mortar than it is for the bricks. Therefore, when the assemblage is compressed, the transverse deformation of the mortar is resisted by the bricks; putting the mortar into triaxial compression and the bricks into bilateral tension. Since all actions have equal and opposite reactions, transverse tensile stresses develop in the bricks because the bricks tensile strength
63


is lower than the compressive strengths of the whole assemblage. Thus, tensile splitting of the prism is the controlling failure mode as shown in Figure 6.3-1. The addition of the fiber optics in this composite material is thought to be were the LTM got its additional strength. Since fibers have superior tensile strength, it was believed that they acted as reinforcement to the overall composite assemblages when the brick units experienced the critical tensile stresses.
Vertical
compression
Figure 6.3-1: Failure Mode in Brick Prism
Figure 6.3-2: Tensile Splitting during Compression testing
In all tested specimens, tensile splitting of the bricks was observed. Moreover, the
tensile splitting occurred at the approximate locations of the cores, which was expected due
64


to the reduced cross-sectional area of brick at those locations. This type of failure is illustrated in the photographs above. It should be noted that the surfaces of the prisms tested during this report were not always completely parallel to each other and could help explain why there was variation in compressive strength results. This was the reason that 4 sets of tests were carried out for each volumetric size and variation of diameter in the fiber optics.
On average, the results proved to be consistent, with fiber reinforced mortar leading to an increase in prism compressive strength. However, the maximum compression values do not substantially increase as the fiber volumetric ratio was increased. Moreover, from the results of varying the diameter of the fiber optics only and keeping the fiber volumetric ratio the same, it appears that the best selection to be used in a final product would be the 1.5 mm diameter fiber optic. This conclusion is based solely on the compression test.
6.4 Shear Strength
From the results of the shear test, it was evident that all test prisms failed in the bonding of the mortar to brick. It was not seen that the addition of any quantity of fiber optics in a joint of mortar weakened the assemblage an any additional way. This is believed to be true given the small diameter of the fiber optics and the fact mortar was allowed to encapsulate the fiber completely. It is thought that if fiber optics were laid side-by-side, touching continuously from end to end of a joint, the possibility of shear failure could occur along this plane, but did not prove this effect to be true. However, it is recommended that at least a 1.0 mm space be left between each piece of fiber optic.
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6.5 Final Thoughts
Combining this information with the conclusion sections above, it is thought that either the 1.5 mm or 2.0 mm diameter fibers are more than suitable for the design of LTM and the final selection should be based on personal preference for the look and quantity of light pixels the architect or owner desires. It is recommended that if the 1.5 mm fiber optic is chosen, then 70 pieces should be used per joint and 40 pieces for the 2.0 mm fiber optics. Based on these numbers, the more economical choice would be the 1.5 mm diameter because there is 2,296 feet on a spool and a manufacturer would be able to make 79 joints worth of material. Whereas, the 2.0 mm diameter fiber optics comes in spools of 1,148 feet and 69 joints could be made per spool. Each spool was purchased for $105 no matter the size at the time of this report.
In conclusion, the development of translucent concrete has paved the way for fiber optics in other materials such as mortar. The fact that the addition of fiber optics not only substantially increases the strength, but also allows for light to be effectively transmitted through mortar, I believe a product like this will be useful to architects and engineers alike.
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Goho, A. (2005). Concrete Nation: Bright future for ancient material. Science News, Vol. 167, No. 1, p. 7, Jan. 1, 2005 http://www.concretewashout.com/downloads /Concrete Nation Science News Online. Jan, E 2005.pdf
Hamid, D. A. Masonry Structures Behavior and Design, 3rd Ed. Boulder, CO: The Masonry Society
Italcementi Group. Available: http://www.italcementigroup.com/ENG/Medi a+and+Communication/News/Corporate+events/20100322.htm
LitraCon. Available: http://www.litracon.hu/proiects.php
Lucem. Available: http://www.lucem.de/index.php7idM56&L=1
Illston, D. a. (2010). Construction Materials: Their Nature and Behaviour. New York : Spon Press.
Masonry Standards Joint Committee (2013) Building Code Requirements for Masonry Structures (TMS-402) Longmont, CO
Masonry Standards Joint Committee (2013) Specification for Masonry Structures Longmont, CO
McGillivray, Sara (2011) Translucent Concrete: An Emerging Material, December 9th, 2011 http://illumin.usc.edu/245/translucent-concrete-an-emerging-material/
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News Desk (2013) Light Transmitting Concrete Panels -A New Innovation in Concrete Technology, September 30, 2013 http://www.masterbuilder.co.in/light-transmitting-concrete-panels-a-new-innovation-in-concrete-technology
Pagliolico, Simonetta L., Lo Verso, Valerio R.M., Torta, Annalisa., Giraud, Maurizio., Canonico, Fulvio., Ligi, Laura. (2015) A Preliminary Study on Light Transmittance Properties of Translucent Concrete Panels with Coarse Waste Glass Inclusions Energy Procedia Volume 78, November 2015, Pages 1811-1816 https://doi.Org/10.1016/i.egypro.2015.ll.317
RTLF.M MS-D.6 (1996) In situ measurement of masonry bed joint shear strength. RILEM TC 127-MS: Tests form masonry materials and structures, Volume 29, October 1996, pp. 459-475.
Sabhapathy, K.S. (2014) Experimental Study of Transparent concrete (translucent) Apr 27th, 2014 https://www.slideshare.net/sabadinesh/transparent-concrete-translucent
Saleem, (2015) System, method and apparatus for providing lane separation and traffic safety, U.S. Patent No. 14/878,583 (2015)
Saleem, Muhammad, Elshami, Mostafa Morsi, Najjar, Muhammad (2017) Development, Testing, and Implementation Strategy of a Translucent Concrete-Based Smart Lane Separator for Increased Traffic Safety Journal of Construction Engineering and Management, Vol. 143, Issue 5, May 2017 http://ascelibrary.org/doi/abs/10.1061/(ASCE)CQ. 1943-7862,0001240#sthash,N7RONrvD.dpuf
Schariff, R. (1989) Workshop Math Sterling Publishing Company
Shanmugavadivu, P.M., Scinduja, V., Sarathivelan, T., Shudesamithronn, C.V (2014) An Experimental Study On Light Transmitting Concrete URET: International Journal of Research in Engineering and Technology, Volume: 03, Special Issue: 11, June 2014
The Economist. (2001) How to see through walls: Transparent concrete is encouraging architects to rethink how they design buildings. Sept. 20, 2001 http://www.economist .com/node/779421
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APPENDIX
Appendix A: Light Transmittance Test (Varying Fiber Volumetric Ratio) Photos
Light Source Before Heat gun After Heat Gun
Figure A.l No Fiber Optics
Light Source Before Heat gun After Heat Gun
Figure A.2 1 mm Dia. Fiber Optics (75 per Joint)
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Light Source
Before Heat gun
After Heat Gun
Figure A.3 1mm Dia. Fiber Optics (150 per Joint)
Light Source
Before Heat gun After Heat Gun
Figure A.4 1.5 mm Dia. Fiber Optics (100 per Joint)
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Light Source
Before Heat gun
After Heat Gun
Figure A.5 2mm Dia. Fiber Optics (75 per Joint)
Light Source
Before Heat gun After Heat Gun
Figure A.6 3mm Dia. Fiber Optics (50 per Joint)
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Appendix B: Light Transmittance Test (Equal Fiber Volumetric Ratio) Photos
Light Source
Before Heat gun After Heat Gun
Figure B.l 1.5mm Dia. Fiber Optics (70 per Joint)
Light Source
Before Heat gun After Heat Gun
Figure B.2 2mm Dia. Fiber Optics (40 per Joint)
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Light Source
Before Heat gun
After Heat Gun
Figure B.l 3mm Dia. Fiber Optics (20 per Joint)
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Appendix C: Compression Test (Varying Fiber Volumetric Ratio) Photos
Figure C.l No Fiber Optics
Figure C.2 1 mm Dia. Fiber Optics (75 per Joint)
74


Figure C.3 1mm Dia. Fiber Optics (150 per Joint)
Figure C.4 1.5 mm Dia. Fiber Optics (100 per Joint)
75


Figure C.5 2mm Dia. Fiber Optics (75 per Joint)
.s wAViv.:\t \x:: v.wrf
, |''M V.NWVf.V.'A1.*:/1

VW(IMU.Va K'V./.1
Figure C.6 3mm Dia. Fiber Optics (50 per Joint)
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Appendix D: Compression Test (Equal Fiber Volumetric Ratio) Photos
Figure D.l 1mm Dia. Fiber Optics (150 per Joint)
Figure D.2 1.5mm Dia. Fiber Optics (70 per Joint)
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Figure D.3 2mm Dia. Fiber Optics (40 per Joint)
Figure D.4 3mm Dia. Fiber Optics (20 per Joint)
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Appendix E: Prism Compression Data Varying Fiber Volumetric Ratio
Specimen Max Force Max Stress
(9-7) No Fiber 49.71 kips 1,798.38 psi
Stress vs Strain
Strain (in/in)
Figure E.l Stress Strain Curve for No Fiber Prism
Specimen Max Force Max Stress
(9-9) No Fiber 52.40 kips 1,895.65 psi
Stress vs Strain
Strain (in/in)
Figure E.2 Stress Strain Curve for No Fiber Prism
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Specimen Max Force Max Stress
(9-11) No Fiber 53.84 kips 1,947.98 psi
Stress vs Strain
Strain (in/in)
Figure E.3 Stress Strain Curve for No Fiber Prism
Specimen Max Force Max Stress
(9-12) No Fiber 64.59 kips 2,336.88 psi
Stress vs Strain
Strain (in/in)
Figure E.4 Stress Strain Curve for No Fiber Prism
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Specimen Max Force Max Stress
(9-7) 1mm 75 55.78 kips 2,017.92 psi
Stress vs Strain
Strain (in/in)
Figure E.5 Stress Strain Curve for 1mm (75 per Joint) Prism
Specimen Max Force Max Stress
(9-9) 1mm 75 70.53 kips 2,551.64 psi
Stress vs Strain
Strain (in/in)
Figure E.6 Stress Strain Curve for 1mm (75 per Joint) Prism
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Specimen Max Force Max Stress
(9-11) 1mm 75 67.84 kips 2,454.27 psi
Stress vs Strain
Strain (in/in)
Figure E.7 Stress Strain Curve for 1mm (75 per Joint) Prism
Specimen Max Force Max Stress
(9-12) 1mm 75 82.93 kips 3,000.13 psi
Stress vs Strain
Strain (in/in)
Figure E.8 Stress Strain Curve for 1mm (75 per Joint) Prism
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Specimen Max Force Max Stress
(9-7) 1mm 150 63.35 kips 2,291.81 psi
Stress vs Strain
Strain (in/in)
Figure E.9 Stress Strain Curve for 1mm (150 per Joint) Prism
Specimen Max Force Max Stress
(9-9) 1mm 150 55.29 kips 2,000.38 psi
Stress vs Strain
3500 3000 2500
S. 2000
to
£ 1500 on
1000 500 0
0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80%
Strain (in/in)
Figure E.10 Stress Strain Curve for 1mm (150 per Joint) Prism
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Specimen Max Force Max Stress
(9-11) 1mm 150 72.41 kips 2,619.80 psi
Stress vs Strain
Strain (in/in)
Figure E.ll Stress Strain Curve for 1mm (150 per Joint) Prism
Specimen Max Force Max Stress
(9-12) 1mm 150 79.11 kips 2,862.23 psi
Stress vs Strain
Strain (in/in)
Figure E.12 Stress Strain Curve for 1mm (150 per Joint) Prism
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Specimen Max Force Max Stress
(9-7) 1.5mm 100 65.84 kips 2,381.94 psi
Stress vs Strain
Strain (in/in)
Figure E.13 Stress Strain Curve for 1.5mm (100 per Joint) Prism
Specimen Max Force Max Stress
(9-9) 1.5mm 100 60.54 kips 2,190.21 psi
Stress vs Strain
Strain (in/in)
Figure E.14 Stress Strain Curve for 1.5mm (100 per Joint) Prism
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Specimen
Max Force
Max Stress
(9-11) 1.5mm 100 68.29 kips 2,470.48 psi
Stress vs Strain
Strain (in/in)
Figure E.15 Stress Strain Curve for 1.5mm (100 per Joint) Prism
Specimen Max Force Max Stress
(9-12) 1.5mm 100 91.92 kips 3,325.58 psi
Stress vs Strain
Strain (in/in)
Figure E.16 Stress Strain Curve for 1.5mm (100 per Joint) Prism
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Specimen Max Force Max Stress
(9-7) 2mm 75 64.35 kips 2,327.95 psi
Stress vs Strain
Strain (in/in)
Figure E.17 Stress Strain Curve for 2mm (75 per Joint) Prism
Specimen Max Force Max Stress
(9-9) 2mm 75 61.13 kips 2,211.56 psi
Stress vs Strain
Strain (in/in)
Figure E.18 Stress Strain Curve for 2mm (75 per Joint) Prism
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Specimen Max Force Max Stress
(9-11) 2mm 75 71.91 kips 2,601.69 psi
Stress vs Strain
Strain (in/in)
Figure E.19 Stress Strain Curve for 2mm (75 per Joint) Prism
Specimen Max Force Max Stress
(9-12) 2mm 75 78.29 kips 2,832.56 psi
Stress vs Strain
Strain (in/in)
Figure E.20 Stress Strain Curve for 2mm (75 per Joint) Prism
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Specimen Max Force Max Stress
(9-7) 3mm 50 69.46 kips 2,512.84 psi
Stress vs Strain
Strain (in/in)
Figure E.21 Stress Strain Curve for 3mm (50 per Joint) Prism
Specimen Max Force Max Stress
(9-9) 3mm 50 70.33 kips 2,544.46 psi
Stress vs Strain
Strain (in/in)
Figure E.22 Stress Strain Curve for 3mm (50 per Joint) Prism
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Full Text

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DEVELOPMENT OF LIGHT TRANSMITING MORTAR by JASON LAMPTON B.S., Texas A&M University, 2003 M.S., University of Colorado, 2017 A thesis submitted to the Faculty of the Graduate School of the University of Colorado in partial fulfillment of the requirement s for the degree of Master of Science Civil Engineering Program 2017

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i i 2017 Jason Lampton All Rights Reserved

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iii This thesis for the Master of Science degree by Jason Lampton has been approved for the Civil Engineering Program b y Fred erick Rutz, Chair Kevin Rens Peter Marxhausen Date: December 16, 2017

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iv Lampton, Jason ( M.S., Civil Engineering Program) Development of Light Transmitting Mortar Thesis directed by Associate Professor Fred erick Rutz ABSTRACT Translucent, or sometimes called tran sparent, concrete is a fairly new concrete based building material with light transmissive properties due to embedded optical fibers into normal cement mix. This report takes this concept to the next level by successfully developing L ight T ransmitting M or tar, or further referred to as LTM. Like translucent concrete where light is conducted through concrete blocks from one side to the other through fiber optics this idea lays optical fibers within the mortar of brick prisms to test the physical and mecha nical properties Although the idea of LTM is thought to be mainly architectural, tests demonstrate that it actually increases the strength of the overall assemblages pretty substantially. This added benefit combined with many possible eye catching patte rns, once lights are placed behind or within the cavity of brick veneer walls, will open the door to many new and stimulating possibilities for future architects and engineers. The form and content of this abstract are approved. I recommend its publicatio n. Approved: Fred erick Rutz

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v TABLE OF CONTENTS CHAPTER I. .. 1 II. ... 3 2.1 Translucent Concr ete: An Emerging Material 4 2.2 LiTraCon ...... 7 2.3 ....... 10 2.4 Light Transmitting Concrete Panels A New Innovation .. 1 7 2.5 Mortar this than meets the eye: The 'transparent' cement 19 2.6 A preliminary study on light transmittance properties of translucent concrete panels with coarse waste glass inclus ...... 2 1 2.7 23 2.8 25 2.9 Development, Testing, and Implementation Strategy of a Translucent Concrete Based Smart Lane Separator for 2 7 III. 31 IV. 32 4.1 ... .......... 34 .. 34 .. 36

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v i .. 38 4.2 .. 39 .. 40 ... 4 1 ... 44 4.3 45 ... ........... 46 ... 4 8 4.3.3 She ... 50 V. 53 5.1 ... .. .. 53 5.2 .. ...... .. 56 5.3 ... ........ ... 58 VI. 61 6.1 6.2 6.3 ............. 63 6.4 ............. 65 6.5 Final Thoughts 6 6 67 69 A. Light Transmittance Test (Varying Fiber Volumetric Ratio) 6 9 B. Light Transmittance Test ( Equal Fiber Volumetric Ratio) 7 2

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vii C. Compression Test (Varying Fiber Volumetric Ratio) 7 4 D. Compression Test (Equal Fiber Volumetric Ratio) 7 7 E. Prism Compression Data 7 9 F. Pr ism Compression Data 9 1 G. Mortar Cube Compression Test 9 9 H. Mortar Cube Compression Data .. 100 I. Shear Test 10 2 J. Shear Test Data 106

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viii LIST OF TABLES TABLE 4.1.1 35 4.1.3 38 5.1 54 5.2 Compressive Stre 56 5.3 60

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ix LIST OF FIGURES FIGURE 1 2 2.1 Translucent Concrete used in art installations in museum exhibits 5 2. 2 .1 7 2. 2 .2 8 2. 3 .1 12 2. 3 2 1 4 2. 3 3 Flexural St 1 5 2.4 Lucem light transmitting concrete panels 1 7 2.5. 1 Outside view of Italian Pavilio ... .............. 19 2.5.2 .. 20 2.5. 3 I .. 21 2.6 2 2 2.7 Schematic layout of a molded block with fixed 2 4 2.8 A c 2 6 2. 9 Functional description of proposed smart lane separator 2 8 4.0 33 4.1.2 37 4.2.1 4 1 4.2.2 1 4 2 4.2.2 2 4 3

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x 4.2.3 4 5 4.3.1 1 Light Transmittance Test Box 4 6 4.3.1 2 ... 4 7 4.3.2 4 8 4.3.3 1 Shear Test Setup 5 1 4.3.3 2 Shear 5 2 5.1 1 5 3 5.1 2 5 5 5.1 3 5 5 5.2 1 Compressive Streng th 5 7 5.2 2 Compressive Strength 5 7 5.2 3 Compressive Strength 5 8 5.3 1 59 5.3 2 Bond Shear Strength vs. 60 6.3 1 6 4 6.3 2 64

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xi LIST OF EQUATIONS EQUATION 2. 3 1 Compressive Strength 1 4 2. 3 2 Flexur 1 5 4.1.1 3 4 4.3.1 4 7 4.3.3 ......... 5 1

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1 CHAPTER I INTRODUCTION The purpose of this thesis will be to analyze the mechanical performance and physical properties of varying the diameter and volumetric ratios of optical fiber to mortar while develop ing a method to manufacture L i ght T ransmitting M ortar ( LTM ) Specifically this thesis analyze s the use of four different diameters of fiber optics ( 1.0 mm, 1.5 mm, 2.0 mm, and 3.0 mm ) to determine such properties as light transmittance, compressive strength, and shear strength A co ntrol sample without the addition of fiber optics w as also tested to serve as a benchmark for the results. There are two primary purposes for conducting this experiment. The first purpose is to develop a new and innovative product where light can be seen through a wall along the mortar joints. As it will further be discussed in the literature review section of this report, Translucent Concrete was invented in 2001 and has been developed by commercial companies over the past de cade. However, there was no mention in the literature of this idea ever being expanded into the mortar between the masonry units of masonry construction The main reason this has thought to be true is fact that mortar is typically applied onsite or in the field and the process of stringing fiber optics effectively in cast concrete has only been proven to be done in manufacturing plants or laboratories. I believe that after showing there are posi tive properties in the process of laying individual short length fiber optics in the m ortar between bricks, a fiber optic mesh can be created to make the process faster and easier in the field. Although the main purpose of creating LTM is thought to be architectural, it turns out there may be other beneficial properties as well.

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2 The second purpose of the experiment is to de termine the mechanical performance and physical properties of adding fiber optics specifically into the mortar between typical clay brick masonry units Through a literature review of translucent concrete, it was found t hat adding fiber optics to concrete slightly increased the strength of the product. However, this report will show that the addition of fiber optics substantially increases the compressive strength to a complete d masonry assemblage. Typically, a masonry assemblage is thought to be stronger than its weakest component (mortar) and is weaker than its strongest component (the brick units). With the addition of fiber optics to this new composite material, this idea continues to be true but gives the added bon us of being abl e to transmit light through the mortar Figure 1: Light Trans mitting Mortar

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3 CHAPTER II LITERATURE REVIEW The literature review of this report is based mainly on the findings and usage of translucent concrete as it is the most comp arable product to LTM and no research could be found on placing fiber optics into the mortar between masonry units The The concrete itself is not actually translucent, nor is it an y different to conventional concrete. Translucent concrete simply contains fiber optics which has the capacity to transmit light from one side to the other of the pre fabricated blocks It is important to differentiate this as past attempts have been made to create an actual translucent concrete. S uch attempts have generally proven unsuccessful as the product becomes fragile, and incapabl e of withstanding wind and rain ( Goho, 2005) Thus, the continuation and development of this idea has led to the Aron Losonczi, first introduced the idea of light transmitting concrete in 2001, then produced the first homogeneous translucent concrete block and named his company Litracon in 200 3 In his process, the translucent concrete blocks are manufactured by layering o ptical f ibers and concrete mix to form a truly homogenous material It can be used for interior or exterior walls, illuminated pavements or even in art and design objects. Litracon claims their concrete has the same strength as regular concrete, if not even slightly higher, and will continue to transmit light through walls up to twenty meters thic k ( Ali, 2014 ). Thousands of optical glass fib ers run parallel to each other between the t wo main surfaces of every block so

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4 s hadows on the lighter side will appear with sharp outlines on the darker one. Even the colors remain the same. This special effect creates the general impression that the thi ckness and weight of a concrete wall will disappear. The idea of LTM uses many of the same ideas found in the journals and articles to follow, as the concept is very similar to translucent concrete. L ike translucent concrete, LTM is thought to be best su ited for interior walls or art and design objects such as benches or an architectural accent wall The basic idea behind LTM will be to place a LED wall wash light bar often found in bars or night club s in a sma ll cavity behind the brick wall or bench The use of spot lights to illuminate desired patterns and designs from an area on the opposite side of an interior wall could also provide an interesting way to allow light to come through its mortar joints The hope is that th is new material will transf orm the interior and possibly exterior, appearance of masonry construction by bringing them to life through illuminating mortar joints with a multitude of color s designs, and shapes 2.1 Translucent Concrete: An Emerging Material ( McGillivray, 2011) In this article, Sara McGillivray dives into the idea, the history and the future of translucent concrete. When you think of concrete, most likely, your mind c onjures up images of something solid, heavy, and monolithic. But what if concrete could be translucent and transmit light into spaces, making them seem light and airy ( McGillivray, 2011) ? This article states that by switching the ingredients of tradition al concrete with transparent ones, or embedding fiber optics; translucent concrete has become a reality. for architects and engineers due to the vast sculptural and expressi ve possibilities that it can

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5 achieve. Concrete has been used since Roman times, but its basic components have remained the same. Three ingredients make up the dry mix: coarse aggregate, fine aggregate, and cement ( The Economist 2001 ) By switching ingr edients and adding new ones, engineers have been able to create a multitude of interesting new products, one of which is tran slucent concrete ( Goho, 2005) In the early stages of creating translucent concrete, they simply exchanged the traditional aggrega tes and the bonding material itself with transparent alternatives to be able to transmit light through clear resins in the mix. (Luxgineer/Wikimedia Common) Figure 2.1: Translucent Concrete used in art installations in museum exhibits A more modern a nd second approach discussed in this article is the combination of optical fibers and fine concrete. This method of producing translucent concrete has been more fully explored and is more common to date than the previous method. This method originally e xplored by the Hungarian Architect Aron Losoncze, uses very fine aggregate to encase optical fibers that allow light to transmit from one side of a block to the other. However, the process is slow and done by hand in a long, narrow mold The optical fi bers and concrete must be manually layered over each other to create a long beam that will

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6 and bond because the proportion of the fibers is very small (4%) compar ed to the total volume of the blocks (Ali, 2014) They are not reinforced in the traditional sense, since the optical glass fibers form a matrix which creates an internal structure of reinforcement. fiber concrete blocks claim a higher compressive strength of 7 252 psi and a surprising tensile strength of 1 015 psi (Ali, 2014) His tests show that glass fibers do not have a negative effect on the well known high compressive strength value of concrete. Rather, fiber reinforcing can mak e translucent concrete even stronger than traditionally reinforced concrete. It has also been found tha t translucent concrete can be an insulating material, protecting against outdoor extreme temperatures while also letting in daylight. This makes it an excellent compromise for buildings in harsh climates, where it can shut out heat or cold without shutting the building off from daylight. In the next few years, as engineers further explore this exciting new material, it is sure to be employed in a variet y of intere sting ways that will change architecture and engineering as we know it. The article did cover some of the negatives or down sides to translucent concrete and currently the cost to manufacture these products tops the list. It was stated at the t ime of this article that it could end up costing about five times as much to build a wall using translucent concrete as opposed to the traditional type ( The Economist 2001 ) This is due to the rarity of the produc t and its experimental nature. Currently there are only a select few companies around the world producing translucent concrete and the process is somewhat low tech and slow. At the time of this article, it was said that it can only be produced as pre cast or prefabricated blocks and panels. T hus, it is mostly being used in interior walls and as decoration, but it is starting to make its venture into exterior structural walls.

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7 2. 2 L i T ra C on Light Transmitting Concrete (Ali, 2014) In 2001, a light transmitting concrete block was invented by Ar on Losoncz i, an architect from Hungry He c oncrete and has sold commercial grade precast manufactured translucent concrete blocks since 2003. LiTraCon has become the leader in the translucent c oncrete devel o p ment and currently holds the patent on the material. This review is based on a slideshow /seminar linked to Li T ra C and outlined key points o f the ir invention building materials and builders have been using concrete for thousands of years. However, the introduction of fiber optics into the concrete mix has given it a new dimension and we are just at the beginning stages of the development of translucent concret e. To understand Losonsz i need to explore the basic component optical fibers, needed to create the matrix of fiber and cement within these light transmitting blocks An optical fiber is a flexible, transpare nt fiber made up of glass or plastic and is often as thin as a human hair. It transmits light between two ends of the fiber by process of total internal reflection and does it so effectively that there is almost no loss of light conducted outside the fibe rs. The optical fiber is made up of three components : (http://www.webclasses.net/3comu/intro/units/unit02/sec04b.html) Figure 2. 2.1 : Components of Optical Fiber

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8 1. CORE (carries light signals) thin glass center of fiber where light travels 2. CLADDING (k eeps light in the core) made of a material which has a lower refractive index than the core. (for light to pass from the core out through the cladding, it would have to slow down. Instead, the light waves take the path of least resistance by reflecting onl y in the core.) 3. COATING (protects the cladding) Plastic coating that protects the fiber from damage. ight transmitting concrete is produced by adding 4% to 5% optical fibers (by volume) into a concrete mixture (Ali, 2014) The fibers nee d to run parallel to each other and the most important requirement for the success of the product is the assurance that the fiber optic strands contact both surfaces; otherwise it loses the ability to transmit light An uninterrupted passage through the c oncrete is achieved by using long molds; which ar e filled with a thin layer of cement then strung layers of fiber optic strands atop the c ement, then more cement is added and the process is repeated until the mold is full. From the long mo lds, the produc t can be removed and then cut to length accordingly to make the size of blocks requested by the client. (Ali, 2014) Figure 2. 2 .2 : Examples of Light Transmitting Concrete

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9 LiTraCon believes that l ight transmitting concrete or translucent concrete is an emerging trend in concrete technology and has created a short list of its advantages, disadvantages and applications that they have found over the years of production: ADVANTAGES: 1. Less energy consumption. 2. Illuminated p avements and roads for safety 3. Homogeneous in structure. 4. Finishing s urface. 5. Routine maintenance not required. DISADVANTAGES: 1. Very high cost ( about EUR 1300/m 2 ) 2. Laborers with technical skills are needed to use it. 3. APPLICATIONS: 1. Sidewalks poured with translu cent concrete could be made with lighting underneath, creating lit walkways which would enhance safety, and also encourage foot travel where previously avoided at night. 2. Translucent concrete walls on restaurants, clubs, and other establishments to reveal how many patrons are inside. 3. Translucent concrete inserts on front doors of homes, allowing the resident to see when there is a person standing outside.

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10 4. The use of translucent concrete in an outer wall of an indoor stairwell would provide illumination in a power outage, resulting in enhanced safety. 5. Subways using this material could be illuminated with daylight. green building material because it can reduce the lightning cost during day time (Ali, 2014) On top of this perk, it has been found to provide both an aesthetic ally pleasing appearance and structural stability The LiTraCon blocks claim to be able to b e used as load bearing walls up to 20 m eters high (Ali, 2014) If the price of the product gets reduced, it is sure that the future of the construction industry will be in the hands of Litracon 2. 3 An Experimental Study on Light Transmitting Concrete (Shanmugavadivu et al, 2014) This article was very helpful in g iving specific numbers and explanations of what exactly goes into light transmitting concrete In the light transmitting concrete discussed in this article, optical glass fibers were thought to form a matrix and run parallel to each other between the tw o main surfaces of a block. The fibers mingle in the concrete because of their insignificant size and they become a structural component as a kind of modest aggregate. The material make up of these blocks can be broken down into these 4 components: 1. CEMEN T As the optical fiber is only responsible for transmission of light, there is no special cement required. So, ordinary Portland cement is typically used for transparent concrete. 2. SAND A naturally occurring granular material composed of finely divided rock and mineral particles. The composition of sand is highly variable, usually in the

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11 form of quartz. Sand particles should pass through 1.18 mm sieve. (The sand used should be free from impurities such as vegetation and gravels.) 3. WATER W hen mixed w ith cement, it forms a paste that binds the aggregate together. The water needs to be pure to prevent side reactions from occurring, which could weaken the concrete. The role of water is important because the water to cement ratio is the most critical fa concrete. 4. OPTICAL FIBERS An optical fiber is a flexible, transparent fiber made of glass (silica) or plastic to a diameter slightly thicker than that of a human hair. Optical fibers are used most often as a means to transmit light between the two ends of the fiber. Light transmitting concrete is a combination of optical fibers and fine concrete that are typically produced as prefabricated building blocks and panels. By arranging thousands of Plastic Optical Fibers (POF) or big diameter glass optical fiber s into concrete, it transmits light so effectively that there is virtually no loss of light conducted through the fibers. Because of their parallel position, the light information on the brighter side of such a wal l appears unchanged on the darker side. The most interesting form of this phenomenon is probably the sharp display of shadows on the opposing side of the wall. Moreover, the color of the light also remains the same. Light travels through the fiber core bouncing back and forth and off the boundary between the core and cladding. Because the light must strike the boundary with an angle greater than the critical angle, only light that enters the fiber within a certain range of angles can travel down the f iber without leaking out. This range of angles is called the acceptance

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12 cone of the fiber. The size of this acceptance cone is a function of the refractive index Currently, t here are three basic types of optical fibers and each vary on how the refractive index between the core and cladding is put together. ( www.cables solutions.com ) Figure 2. 3 .1 : Types of Optical Fiber 1. MULTI MODE STEP INDEX FIBER This fiber is called "Step Index" because the refract ive index changes abruptly from cladding to core. The cladding has a refractive index that is somewhat lower than the refract ive index of the core As a result, all rays within a certain angle will be totally reflected at the core cladding boundary. Ray s striking the boundary at angles greater than the critical angle will be partially reflected and partially transmitted out through the boundary. After many such bounces the energy in these rays will be lost from the fiber. The paths

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13 along which the ray s of this step index fiber travel differ depending on their angles relative to the axis. 2. MULTI MODE GRADED INDEX FIBER In graded index fiber there are many changes in the refractive index with larger values towards the center. Light travels faster in a lower index of refraction. So, the farther the light is from the center axis, the greater is its speed. This means that each layer of the core refracts the light with a different refractive index. Instead of being sharply reflected as it is in a step i ndex fiber, the light is now bent or continuously refracted in an almost sinusoidal pattern. In theory, those rays that follow the longest path by traveling near the outside of the core have a faster average velocity and the light traveling near the cente r of the core has the slowest average velocity. As a result, all rays tend to reach the end of the fiber at the same time. That causes the end travel time of different rays to be nearly equal, even though they travel different paths. 3. SINGLE MODE STEP IN DEX FIBER Another way to reduce modal dispersion is to reduce the core's diameter, until the fiber only propagates one mode (ray) efficiently. The single mode fiber has an exceedingly small core diameter of only 5 to 10 m. Standard cladding diameter is 125 m. Since this fiber carries only one mode, model dispersion does not exist. A multimode fiber can propagate hundreds of light modes at one time while single mode fibers only propagate one mode as shown above The properties of light transmitting con crete a re determined by conducting various experiment s like compressive strength and flexural strength tests A typical transparent

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14 concrete block, in the testing of this article, is shown below with mix propo rtions and dimensions as follows : (Shanmugavad ivu et al, 2014) Cement 360 kg Sand 560 kg Fiber 4.5 kg Water 190 lit er Size: 150mm x150mm x 150mm The compressive strength of a material is that value of uniaxial compressive stress reached when the material fails completely. The compressive strength is usually obtained experimentally by means of a compressive test and using the following equation: Compressive S trength = P / A Where: P = Load applied A = Area of prism (Shanmugavadivu, et al, 2014) Figure 2. 3 .a: Compressiv e Strength

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15 (Shanmugavadivu, et al, 2014) Figure 2. 3 .b: Flexural Strength The compressive strength and flexural strength of the conventional concrete and light t ransmitting concrete in 7, 14 and 28 days is shown in F igure: 2 3.a and 2.3.b respectfully. T he flexural strength of the concrete was determined by conducting the test on a prism by way of two point loading and using the following equation. Flexural S trength = Pl/bd 2 Where: P Load l Length of the specimen b Width of the pri sm d Depth of the prism After the compressive and flexural strength results of the decorative concrete were correlated with the results of ordinary plain cement concrete, the results show that the performance of light transmitting concrete is slightly h igher than ordinary cement. Hence,

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16 the application of optical fiber will make the concrete structurally efficient as well as decorative. Thus, the study concludes that the transparency of light is possible in concrete without affecting its compressive st rength and the optical fibers can act as a fiber reinforcement, thereby enhancing the strength as well as the appearance. T his article also listed some other notable properties of the light transmitting concrete found through different tests : (Shanmugavad ivu et al, 2014) 1. Permits the passage of light through the set concrete; permitting colors, shapes and outlines to be seen through it. 2. Having compressive strength of 7,2 50 32,00 0 psi 3. Having maximum water absorption of 0.35% 4. Having a maximum oxygen inde x of 25% 5. Having a thermal conductivity of 0.21 W/m C 6. Having a flexural strength of 1.1 ksi 7. Having an elastic limit greater than 8,700 psi 8. Having a density from 13 0 to 150 lb/ft 3 9. Having a Young's Modulus from 400 ksi to 5 0 0 ksi 10. From its characteristic s and composition, it can be a conductor of electricity. 11. From its mechanical and optical characteristics, it can be used for purposes that are both architectural and aesthetic, as well as structural.

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17 2. 4 Light Transmitting Concrete Panels A New In nova tion in Concrete Technology (News Desk, 2013) This article talks about how German concrete manufacturer, Lucem L ichtbeton, is thought to be one of the other leading companies involved in the production of light transmitting concrete. In conjunction with A achen based architects, Carpus & Partner, Lucem produced 150cm by 50cm concrete panels containing optical fibers and placed them along a wall; forming a total area of 30m wide by 4m high with 136 panels. Each panel was fitted with color changing technolog y and controlled using an internet based DMX technology system. The technology controlling the lights opens new boundaries for design and architecture as the light panels are made with red, green and blue chips to allow more than 16 million color options. In fact, all the panels can be controlled independently meaning the entire facade can become a large display screen. The light shows on the wall can be controlled via the internet or a mobile device and interactive elements as well as text and logos can be displayed on this wall (News Desk, 2013) ( www.lucem.com) Figure 2.4: Lucem light trans mitting concrete panels at RWTH Faade, Aachen

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18 According to the Lucem website there are currently three different types of Lucem Lichbeton panels, which offer different effects and aesthetics for the user. These panels have various uses including, but not limited to: facades, interior walls, claddings, flooring systems, room dividers and bars. With the Lucem Label panels, light transmitting fibers are arrang ed individually so that clients can display design logos, images, names, signatures and icons on the panels. Some additional application areas and examples of Lucem mentioned in this article were (News Desk, 2013) : 1. CLINIC GENK ( surgical clinic, partitio n wall ) The new building of an oral surgery clinic presents a large sized Lucem wall used as a room divider. A brightly illuminated waiting area induces an interesting shadow play on the part of the offices. 2. NESSELANDE, ROTTERDAM, OUTSIDE ILLUMINATION ( promenade at overpark ) In Rotterdams district Nesselande, a local recreation area was created. Long bands of concrete were integrated into the landscape enclosing the greenery on the one side and being a bench on the other side. 3. SIGNAL IDUNA ( Extens ion of the main administration building of Signal Iduna insurances, Dortmund ) Lucem light transmitting concrete panels were used as accents for the entrance hall and the executive suite. The Lucem Line panels have been designed as floor to ceiling wall c laddings utilizing free space behind the panels for a light supply.

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19 2.5 Mortar this than meets the eye: The 'transparent' cement that lets daylight flood into a room ( Bates 2011) In this a rticle, a team of architects have created a new way of making transparent cement panels that lets light pour into a room so that the walls look like giant windows. These Italian architects operate under the company name Italcementi a nd believe that their research is a strategic asset aimed at creating innovative projects that follow up new market trends. In 2010, they took up the challenge to build the Italian pavilion for the Shanghai Expo because they wanted to find a creative, eff icient solution for a cement material to be special resins inside of dozens of tiny holes to let light through without compromising the structural integrity. The des ign is to appear to have its surface transparent from a far, but up close the tiny resin filled holes that make up the panels can be seen (www.italcementigroup.com) Figure 2.5. 1 : Outside view of Italian Pavilion for the Shanghai Expo

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20 I light SHANGHA I gets its namesake from its original purpose for the invention, the Italian pavilion. Italcementi used i light for around 40% of the 18 metre high Expo pavilion. Three thousand seven hundred and seventy four transparent and semi transparent panels were made from 189 tons of the product. (www.italcementigroup.com) Figure 2.5. 2 : Tiny resin filled holes T here are approximately 50 holes i n each transparent panel, leading to about 20% transparency. Its transparent characteristic is not only able to trans mit natural and artificial light, but also allows the human eye to see images and objects placed behind the panel. During the day, external light seamlessly filters into the building creating a new and suggestive atmosphere as the sun light intensity varie s throughout the day. At night the effect becomes magical, with internal light seeping back through the panels and making the building become alive. Thanks to this, the architectural structure itself creates a show that has never been seen before.

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21 (www .italcementigroup.com) Figure 2.5 .3 : Inside of Italian Pavilion for the Shanghai Expo Previous attempts at a similar feat had been tried using fiber optic cables, but Italcementi claims its version is better. Enrico Borgarello, Italcementi Gr oup Innovatio n The transparent cement made from plastic resins is much cheaper than the one made from optical fibers. Moreover, the ability to capture light is greater, since the resins contain a wider visual angle than optical fibers ( Bates 2011) The technology used to build i.light panel s guarantee a degree of light angle of incidence higher than optical fibers T he cost of i.light is also at least 10 times lower than the same material o btained using optical fibers. 2.6 A preliminary study on light transmittance properties of translucent concrete panels with coarse waste glass inclusions (Pagliolico, et al, 2015) This paper investigated the use of coarse g lass waste imbedded in cement to make precast translucent concrete panels. Waste pieces of glass that were found to have flat and

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22 coarse physical properties were enclosed and surrounded with a concrete mix to extend from one side to the opposite side of t he panel, enabling light transmission through the wall. (Pagliolico, et al, 2015) Figure 2.6: Light Transmitting Panel B uilt with Waste Glass The panels were designed as non load bearing panel prototypes and thought to be used as interior walls to tr ansfer natural light and lower energy costs required to il luminate a room. The panels were manually prepared, positioning the glass inclusions to make sure the insid e the mold, self compacting mortar was added all around the flat glass scraps. The mortar mix consisted of a white cementitious high performing binder, dry siliceous sand, potable water, superplasticizer and a de foamer. After the panels were constructed, an array of 16 miniaturized illuminance meters was used to measure the illuminance distribution across the panel. Measurements were taken with and without the panel to form a basis for the data on both light transmission and energy arou nd the testing are a. Although the authors noted the best way to measure the light

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23 transmission of the panels would be to employ the use of a photo goniometer, they stated this kind of equipment would be used at a future stage of the research. From the equipment they had access to and the tests that were conducted on these panels, it was determined that the glass inclusions were classified as non reactive under the accelerated Alkali Silica Reactivity ( ASR ) test. Furthermore, the light transmission tests resulted in a ran ge of 1.3% to 4.9% of light allowed through the wall (Pagliolico, et al, 2015) Computer simulations were also carried out to compare the light transmission in a sample room with two sided internal walls. They came up with a similar value of light transm ission topping out at 5%. However, the energy demand for lighting inside the room still decreased in a range of 12.7% to 16% because the amount of natural light that was let in due to these panels (Pagliolico, et al, 2015) 2. 7 Experimental Study of Tra nsparent concrete (Sabhapathy, 2014) M any kinds of tests were done in this article t o ev smart transparent concrete. This included a white light test (to determine the amount of light transmission), freezing thawing test an d chloride ion penetration test (to determine long term durability), and stress elasto optic effect test (to determine self sensing properties). In a nut shell, the experiments results show that the smart transparent concrete has good transparency, mechan ical and self sensing properties. Many of the properties of fiber optics, listed below, contributed to the success of these tests and why they are used in other industries as well (Sabhapathy, 2014) The life of fiber is longer than copper wire Handling and installation costs of optical fiber is very nominal

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24 It is unaffected with electromagnetic interference Attenuation in optical fiber is lower than coaxial cable or twisted pair. There is no necessity of additional equipment for protecting against gr ounding and voltage problems, as it does not radiate energy. Any antenna or detector cannot detect it, hence it provides signal security With the help of fiber optics, c oncrete is no longer the heavy, cold and grey material of the past; it has become beau tiful and lively. By research and innovation, newly developed concrete has been created which is more resistant, lighter, white or colored, and now transparent. It can be used to better the architectural appearance of the building and even used where lig ht cannot reach with appropriate intensity. This new kind of building material can integrate the concept of green energy saving s with the usage of self sensing properties and promises to be the building material of the future (Fathima, 2015) Figure 2 .7: Schematic layout of a molded block with fixed fiber composites within the framework an industry never thought to need it. Optical fibers pass as much light as tiny slits when they

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25 are placed directly on top of each other. Hence optical fibers act like the slits and carry light throughout the concrete, but maintain the compressive strength of normal concrete without the voids or slits weak ening the product. On top of this, the manufacturing process of transparent concrete is almost the same as regular concrete. The only difference being that small layers of fibers are infused into the concrete as the fine concrete mix is poured into the m old and on top of each layer of fibers. Fibers and concrete are alternately inserted into molds at intervals of approximately 2 mm to 5mm. This allows t he transparent concrete to have good light guiding properties and should be noted that the ratio of op tical fiber volume to concrete is proportion to the transmission of light. 2. 8 Computational Modeling of Translucent Concrete Panels (Ahuja, et al, 2015) This study investigated a novel building envelope material that consists of optical bers embedded in concrete A computational model of how light and heat is transferred through them was also done to further their research especially during peak time of the day and year. In their research on such material, it was found that the introduction of effective daylight responsive systems can reduce the operating costs of conventional lighting systems by 31% on an annual basis. Under their literature review, they found four notable steps in the history of translucent concrete that were worth mentioning. In 2001, Hungarian architect Aron Loson c Th e University of Detroit Mercy also developed a process to produce translucent pan els made of Portland cement, sand and small amount s These panels,

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26 which were only 2.5 mm thick at their centers, were it was thin enough to be transluce nt under direct light. Then, d uring the 2010 World Expo in Shanghai China, Italy modeled its pavilion out of translucent concrete using approximately 4,000 blocks created by Italecementi and later named them i light Another form of translucent concrete featured larger pl and was developed by Bill Price of the University of Houston to further his research on translucent concrete He named his work Pixel Panels and is known for research of translucent concret e rather than commercial manufactur ing T his study utilized the design of the Pixel Panels a s a basis for their computation and conclusions drawn below. Their paper presented a geometrical ray tracing algorithm to simulate light transmission properties of the proposed translucent concre te panel. For simulation purposes, a translucent concrete panel was modeled as a cuboid with dimensions 0.3 x 0.3 x 0.1 meters. The transparency of the translucent concrete panel was varied by simulated for multiple tilt angles from 0 degrees to 60 degrees (in intervals of 5 degrees) to compute an angle that would transmit maximum light for the whole year. It was then (Ahuja, et al, 2015) Figure 2.8 : A computational model of transparent concrete panel

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27 It was also discussed and worth mentioning that as light travels through the core of the fiber optics it suffers two types of intrinsic losses: 1. Light scatterin g 2. Light absorption from electronic transitions between the excited and the ground states. the scatter different spectra primarily was due to absorption. They could then conclude that a translucent concrete panel admits more heat than a high performance window during the year; which is helpful in reducing heating loads during winters, but potentially increases the cooling load for the air conditioning unit of the building during summer months (Ahuja, et al, 2015) 2. 9 Development, Testing, and Implementation Strategy of a Translucent Concrete Based Smart Lane Separato r for Increased Traffic Safety ( Saleem, et al, 2017) This paper detailed the development, testing, and real world applica tion strategy for a new translucent concrete based lane separator. The proposed device would be embedded into the road surface and can be used for transferring real time information to the road users. The developed device can transmit colored light by em bedding plastic optical fibers in the self compacting concrete. The self compacting concrete was prepared based on its increased workability, which allowed it to flow in corners and small areas around the optical fibers placed in the mold. Cube specimens were also cast to check the compressive strength of the

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28 developed concrete and to evaluate the percentage of light passing through the fibers. The minimum compressive strength requirement was set at 35 MPa to account for large trucks driving over the road way. The self compacting concrete was made per the following specifications ( Saleem, et al, 2017) : ASTM C150 ordinary Portland cement (Type I was used as a binding material) Dune sand was used as fine aggregate Crushed limestone was used as coarse aggreg at e with a maximum size of 9.5 mm Polycarboxiate ether based superplasticizer was added to the mix as 0.5% by volume of cement in order to give the mix the desired workability The mix constituent contained ordinary Portland cement, fine aggregate, and m edium aggregate of a 1, 1.7, and 2 ratios respectively The cement content was 370 kg/m 3 an d water to cement ratio was 0.4 (Saleem, 2015) Fig 2.9 : Functional description of proposed smart lane separator Plastic optical fibers (POF) were wound into tend ons, of which each tendon was composed of 12 optical fibers wound together into a single piece. The tendons were then

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29 placed through the predrilled holes of the molds and were secured in place by adhesive glue. It was found that the volume of optical fib er in the concrete was proportional to the light transmitting capability of concrete and would be determined through trial and error. Various samples, for compressive strength testing, were prepared by replacing different percentages of fibers to that of concrete. From trial and error approach, 3% volume replacement was noted to be the optimal percentage because it resulted in the least loss of strength while giving the desirable translucency. Loading was applied parallel to the POF tendons during testin g in order to simulate the real world application condition. There was found to be an 11.14% reduction in strength, which is considerably lower than that reported in their literature research of approximately 35% ( Saleem, et al, 2017) They believe they achieved this by roughing the surface of the POF tendon so the bond between the tendons and concrete could be improved, which leads to the increase in compressive strength. A light transmissibility test was also performed using a light meter TECPEL 530 to calculate the percentage of light passing through the POF tendons. Keeping in mind the extreme temperatures that the road surface is subjected to during its life cycle, it was also decided to conduct a detailed temperature testing of the cast specimens It was seen that the specimens were successfully able to sustain high temperatures, and the optical fibers did not melt, even after being exposed to 225C for a long period of time. Because the operational temperature of the road is between 60 and 80C it can be concluded that the proposed device is suitable for road implementation ( Saleem, et al, 2017) This article is very thought provoking because it takes the idea of translucent concrete and turns it on its side, literally. This idea uses the fibe r optics in a vertical setting and in sense places a light behind them to allow illumination from the ground up. Furthermore, the

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30 article talks of how the fiber optics can withstand weathering and even the weight of vehicles with cyclic loading. It is in teresting how different ideas are coming out of the development of translucent concrete, not only for an eye pleasing architecture but road safety as well. This idea could be expanded into the idea of LTM too Perhaps placing emergency lights behind a wa be used for fire escapes and lighted pathways or even warning signs in the case of an emergency.

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31 CHAPTER III PROBLEM STATEMENT A multitude of articles and publicatio ns regarding translucent concrete, or light transmitting prefabricated concrete blocks, has generated interest by architects since the invention in 2001. Although translu cent concrete has emerged as a new construction material, there has been little to no discussion or claims on work towards a light transmitting mortar and the development of it will be the first goal in this experiment The second goal of this report is to analyze the mechanical performance and physical properties of several different dia meters and volumetric ratios of optical fiber to mortar in typical masonry assemblages Tests use d unjacketed end glow fiber optics that were commercially manufactured and readily available. Two concurrent assessments were made to determine the best diam eter and volumetric ratio. The first assessment was done by varying the volumetric ratios, of fiber optics to mortar, from 2.5%, 5%, 7.5%, 10% and 15%. The second assessment used equivalent volumetric ratios, but vary the fiber optics diameter of 1.0 mm, 1.5 mm, 2.0 mm, and 3.0 mm. The selection of the best diameter and volumetric ratio was based on the results of the light transmittance, compressive strength, and shear tests between these two assessments. The mortar design mixture remain ed unchanged for each fiber volumetric ratio and a control sample of 0% fiber volume ratio was tested to serve as a benchmark for current masonry work and to validate the results.

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32 CHAPTER IV EXPERIMENTAL PLAN For this experiment, four sets of solid prisms consisting of five standard modular clay bricks with type N mortar and fiber optics were assembled and tested. The joint thickness of all prisms was specified to be inch thick in order to fit the varying size s and quantities of fiber into the mortar across both te sts. Bricks for the prisms were collected from the same stockpile and it was assumed that the bricks used all possessed similar compressive strengths individually. The mortar mix was made using a 3:1 mix of clean, all purpose sand and typical mortar ceme nt as is specified to prepare Type N mortar. The sand to mortar mix ratio will remain the same throughout all batches and verified by weight. The water was supplied by the taps within the laboratory, which provide potable water from the local water autho rity, Denver Water. Initial water contents were the same by measurement, but water was added on an as needed basis to achieve the desired mortar workability. The prisms were all assembled in the laboratory at the civil engineering department of the Unive rsity of Colorado Denver and created under normal temperature, atmospheric pressure, and humidity relative to Denver, Colorado in the month of August 2017. Upon completion, all prisms were stored in the same area of the lab and let to cure at room tempe rature for 14 days prior to testing. In order to confidently test the mechanical and physical properties as outlined in the problem statement of this report, four specimens from each volumetric ratio were made and tested T he first assessment of a given set is based on the maximum number of fiber optics that could p hysically fit in a inch joint and varying volumetric ratios This maximum was achieved by laying two rows of the fiber optics per joint. It should be noted that the fiber

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33 optic diameters an d quantities varied in this group to produce volumetric ratios of 2.5%, 5%, 7.5%, 10% and 15%. The second assessment, within this same set, is based on f our different sized diameter fiber optics of 1.0 mm, 1.5 mm, 2.0 mm, and 3.0 mm with similar volumetri c ratios of about 5%. A control sample without the addition of fiber optics, or volumetric ratio of 0%, was also built to serve as a benchmark for the results. A set of three brick prisms were then made to test the shear strength and evaluate the locatio n of failure when lateral forces may be applied to the masonry assemblages. These prisms were created in the same way as above, but only used three bricks so they could be turn ed on their side and place d in a 3 point bending setup. This set of prisms w as created based solely on varying volumetric ratios and the maximum amount of fiber optics that could be placed in a given joint because it was thought the best chance of failure due to the fiber optics would be achieved when the most fibers optics possible were put into a joint Figure 4.0: The m aking of mortar cubes Mortar cubes, without fiber optics, were also cast from each batch throughout the

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34 set of prisms laying four bricks together as illustrated in Figure 4.0 To replicate water absorption that would be expected to occur if the mortar were used in prisms (or in the field), paper towels were used in lieu of any other bond release agent to facilitate the removal of the cubes from the brick forms. 4 1 Properties of Light Transmitting Mortar 4. 1 .1 Fiber Volume Ratio The components that make up LTM consists simply of a mortar mix and optical fibers. This idea is achieved by laying optical fibers into the mortar mix so that the fiber optics reach from one side of the brick to the other. This allows light to be transmitted from one side of a wall to the other through the fiber optics. Commercially developed fiber optic s can come in a variety of types, but typically are made of either plastics and glass. The basis for many of the tests in this experiment are based on volumetric ratios of fiber to an individual joint. This volume ratio V f is found by taking the total volume of fibers and dividing it by the overall volume of the composite mortar. V f = (v f /v c ) x 100% Where: V f = Volume Ratio of Fibers v f = volume of fibers v c = volume of composite mortar The fiber optic vol ume tric ratio for LTM will be used throughout the experiment as the controllable variable. This will not only pertain to the ability of the mortar to transmit

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35 light, but also to test physical qualities like compressive strength as well. It should be note d that several manufacturers have stated that the addition of the plastic or glass optical fibers has also increased the tensile and flexural capacity of concrete products, but these properties are beyond the scope of this report and were not tested on the LTM (Illston, 2010). The first assessment of prisms was sought to test varying volume tric ratios to find the effects of increasing the amount of fiber optics within the mortar. The volume tric ratios of fiber to mortar were selected based on limiting spa It should be noted that to achieve the larger volume tric ratios, one must increase the diameter of the fiber optics as well as the quantity of them. The second assessment of prisms were all specified to have equal volume tric ratios in order to find differences in increasing diameters of the fiber optics. The calculations of the volumetric ratios and the number of fiber optic pieces are show in the table below. Table 4.1.1: Volume tric Ratio Design Tabl e

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36 4. 1 .2 Optical Fibers Fibers can be used in either multifilament or monofilament arrays. Multifilament fibers will consist of a bundle or grouping of fibers where individual filaments may or may not be in contact with the mortar mix Some designers wi ll use this characteristic of bundles to allow the bundles to remain flexible in the core of the grouping where fibers are not bonded with the mortar adding additional ductility to the reinforcing fibers. Monofilament fibers consist of a single fiber all owed to fully bond with the surrounding m ix For the purposes of this study we will be examining the behavior of monofilament plastic polymer fibers cut to a length of 5 inches and placed within the mortar joint of the prism. In order to explain the basi c principles that allow these small fibers to transmit light so efficiently we must first understand the components of a typical light guiding optical fiber. The main body of the fiber is made up of the core and is typically manufactured by extrusion of a silica glass or polyethylene melted into a liquid form which is then pulled into the desired diameter. These fibers are then dipped into a cladding mixture which will have a lower refractive index than the inner core. This allows in candes cent light waves on the inner core to propagate along the length of the fiber continuously reflecting against the cladding This leads to total internal reflection which allows the light to travel relatively large distances with little to no power loss. A general exampl e of the entrance and reflectance of light in an optical fiber can be seen in Figure 4 .1.2 Some typical light guiding fiber optics can allow light to travel over 1 km wit h approximately 3.6% power loss. M ost people see this application in everyday fiber optic cable television transmission. For the application of LTM, we are less concerned with the amount of light loss as the transverse distances traveled are relatively small in comparison.

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37 The numerical aperture of a fiber is a value ranging from 0 to 1 and is used to quantify the incident angle of light able to enter the face of the core. The cone traced out by this acceptance angle is known as the acceptance cone. (https://en.wikipedia.org/wiki/File:Optical fibre.png) Figure 4 .1.2 : Optical Fiber Prin ciples Light entering the core within the acceptance cone propagates the length of the fiber, whereas light entering the core at an angle greater than the acceptance angle is only guided along a very short distance along the fiber where it continuously ref lects and eventually dissipates. A refractive index describes the ability of the material in which the light is traveling to propagate in cand escent light. Cladding will have a lower refractive index than the core it encloses which allows light to efficie ntly be reflected through the core. If the cladding had a larger refractive index the light traveling through the core would pass through the cladding and lead to less efficient light transfer. This study used Polymethyl Methacrylate Resin fibers without a cladding. The use of a cladding would provide for more efficient optical fibers, but for the relatively short transverse distances of the width of bricks used in this experiment unsheathed optical fibers were selected.

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38 4. 1 .3 Mortar Design Mixture Mor tar is a workable paste used to bind building blocks such as stones bricks and concrete masonry units together. Cement mortar becomes hard when it cures, resulting in a rigid aggregate structure; however the mortar is intended to be weaker than the building blocks and can be a sacrificial element in the masonry. Mortars are typically made from a mixture of sand a binder or cement, and water. The ASTM Standard C270 (Mortar for Unit Masonry) provides the basis for specifying cement lime mortars. This specification provides the basis for five different mo rtar types (Type M, S, N, O, and K) depending on the strength of mortar needed for an application. (These type letters are taken from the alternate letters of the words "MaSoN wOrK"). Type M mortar is the strongest, and Type K the weakest. The Appendix of ASTM C270 provides a reference to which mortar type should be us ed in some general applications and a n adapted version of this list is shown in Table 4.1.3 Table 4.1.3: Mortar type for some general applications Mortar Type Location Use Recommended Alternative Exterior, above grade Load Bearing Wall N S or M Non Load Bearing Wall O N or S Parapet Wall N S Exterior, at or below grade Foundation Wall or Retaining Wall S N or M Pavements, Walks or Patios S N or M Interior Load Bearing Wall N S or M Non Load Bearing Partitions O N From the table above, and availability at a local hardware store, T ype N mortar wa s selected for this experiment as a realistic application for a wall with LTM For a basic mortar mix, it was prescribed t o mix essentially three parts of sand for every one part of cement

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39 use d That means if mixing up a whole 70 pound bag of cement, the prescribed amount will use three times that of sand and will result in a large batch of mortar mix. Due to the time it t akes to individually lay the fiber optics into the joints, only 6 pounds of cement and 18 pounds of sand where mixed per batch Although i t has been said that the measur ement do need to be precise as a baking recipe it was kept equivalent from batch to batch for the integrity of the experiment. At most work sites, when mixing large amounts, the amount of sand is usually given in "shovels full" per bag of mortar mix, which usually works out to somewhere between 15 and 18 scoops depending on how larg e the shovel scoops are. 4. 2 Manufacturing Methods It is essential that methods of creating test prisms and the tests themselves remain equivalent as possible to limit eccentricities and anomalies that could be found later It is also vital in the exper imental process that all variables are controllable and only one variable is changed at a time. This way it is clear what is affecting the results. In saying that, great measures were taken to make sure the only variable in this experiment that was chang ed was the volumetric ratio of fiber optics to mortar within each joint. Further research shall be done to test other variables such as the direction or spacing of the fiber optics. A freeze thaw test or heat testing could also be done in the future to t est the durability of the fiber optics in harsh weather conditions. For this thesis, one person mixed every batch of mortar, laid each fiber optic individually, and placed every brick across all specimens to limit the number of uncontrollable variables. The bricks were obtained from the same stock pile and the fiber optics were ordered from the same distributor. Each set of prisms were created one after another on individual days, but allowed exactly the same amount of time to cure before testing them Meaning if the first set was created on a Monday, it was tested two weeks later

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40 on a Monday around the same time. The testing apparatuses and data acquisition programs were also the same amongst every test and loaded by the same individual. The following manufacturing methods were closely followed to produce the LTM prisms studied in this report and attention to every detail was well documented 4. 2 .1 Setup and Preparation The fiber optics came in rolls of 4,920 feet for the 1.0 mm diameter fiber ; 2,296 f eet for the 1.5 mm diameter fiber ; 1,148 feet for the 2.0 mm diameter fiber ; and 492 feet for the 3.0 mm diameter fiber. These were needed to be cut down to lengths of 5 inches to allow the fiber optics to extend past the width of the brick. The calculat ion of number of fiber optics needed we re shown in T able 4.1.1 of the previous section and tracked as some pieces were cut by hand and others were sent off to be cut commercially After a few trial and error attempts to cut this many pieces by hand, the se rvices of Allcable Inc. was enlisted to have the fiber optics cut mechanically by a large machine seen in Figure 4.2.1. They we re able to take the spools and load them into large machines that would then send the fiber optics through rollers to measure o ut exactly 5 inches and simultaneously slice the pieces into a hopper. This dramatically reduced the amount of time it took to do by hand and actually helped straighten the pieces a bit from the inherent curve that was created from being on the spools T he only other step that was done by hand was separating the fibers into bags with the quantities specified by the volumetric ratio calculations; this way one bag c ould be used per joint as the prisms were built.

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41 Figure 4.2.1: Machine at Allcable, Inc. to cut fiber to length It is noted that for future tests a manufacturer will be found to produce a mesh of fiber optics with the same spacing and lengths in order to reduce even more variables. Not much time was spent looking for a manufacturer to cut the pieces to length because it was thought cutting them by hand would not be an issue. This proved to be the first major road block of the manufacturing process, but opened up new ideas for future testing and how enlisting the services of an established man ufacturer can help in many ways. 4. 2 .2 Building the Prisms Once the fiber optics were put into individual bags, it was easy to make sure the exact number of fibers specified were placed inside each joint. To build an individual test prism, it

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42 is best t o set everything up in a smart workable area, meaning all the bricks for each prism are easily accessible and the bags of fiber optics for the 4 joints are ready to be used. A batch a mortar shall be mixed per the specifications discussed in the previous section and kept moist for good workability. To make test prism s the steps below were followed : Figure 4.2.2 1 : Building a typical mortar joint with fiber optics 1) Make sure the first brick is level (it will be crucial for testing that the bottom surface is parallel to the top surface) 2) Then a thin layer of mortar should be placed and tro wel ed over the top of the first brick (make sure the top part of the brick is completely covered) 3) A layer of fiber optics can now be laid on top of the thi n layer of mortar 4) Tro wel another thin layer of mort ar on top of the fiber optics 5) Place the next brick of this prism on top of the composite bed of mortar 6) Tap the brick down with the butt of the tro wel to sit in the mortar

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43 7) Take measurements to mak e sure the joint thickness is inch throughout as specified (It is also crucial to make sure the top brick is still level and aligned with the brick below) Figure 4.2.2 2: Keeping it consistent 8) Repeat steps 1 7 unt il a 5 brick prism is comp lete 9) Once the prism is complete, label it with the date created, the diameter and the number of fiber optics used in said prism 10) Set the prism in a secure area of the lab to let cure. Once a pri sm was complete for a given diameter o f fiber optics th e process was repeated for t he next diameter of fiber optics before the same specimen was repeated. A set of specimen s consisted of the following diameter and quantities of fiber optics per joint: Mortar o nly 3.0 mm diameter wit h 20 fibers 2.0 mm diamet er with 40 fibers

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44 1.5 mm diameter with 70 fibers 1.0 mm diameter with 150 fibers 3.0 mm diameter with 50 fibers 2.0 mm diameter with 75 fibers 1.5 mm diameter with 100 fibers 1.0 mm diameter with 75 fibers mortar only done once per set, but the data was used for both assessments. Three batches of mortar were needed to complete each set and a complete set was done by one individual in about 3 to 4 hours straight through. Four se ts of specimens were constructed the same way on different days to limit the variables within a set. A set of 3 brick prisms were created in the same way for shear testing. 4. 2 3 Grinding and Polishing After a week of letting the prisms cure, the mortar was strong enough to come back and g rind off the excess fiber and mortar. This was done to give the wall a clean and flush look that would normally be see n with brick masonry, but also to make sure that the fiber optics reached completely from one side t o the other and the ends were not covered with dry mortar If fiber optics were exactly the width of the brick, it is possible that the mortar c ould cover the ends of the fiber, thus not allowing light to transmit through the wall. Grinding or flush cutt ing the fiber optics also allowed for a new smooth end to have a better acceptance disk and seen in F igure 4.2. 3 a and 4.2.3b :

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45 a) b) c) Figure 4.2.3: Grinding & Polishing During testing, it was thought that using a heat gun would melt the ends of the fiber optics and polish them over to improve light transmission as well Testing wa s done before results outlined in further sections show it d oes make an improvement of the measured lumens transmitted through the mortar. The heat gun was turne d on high and run along the joint at about a rate of 1 inch per 2 3 seconds as shown in figure 4.2.3 c It was noticed that when using the heat gun, the fibers start to melt and pull ed back into the voids of the mortar. However, because the solid mortar a cted as a sort of cladding it appeared that it was not possible to over melt the fiber optics at the rate used in this experiment 4. 3 Testing Methods The prisms were all tested for light transmission, compression strength, and the whereabouts of shear f ailure. Light transmitting data as well as load to deflection data was collected and analyzed in subsequent sections.

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46 4. 3 1 Light Transmittance Test The light transmittance test will measure the illuminance of light transmitted through the LTM by way of t he plastic optical fibers. Illuminance measures the luminous flux per unit area. In this report all measurements of illuminance will be i n Lux units. Luminous flux is the unit of measurement used in lighting photometry that describes the amount of power produced by a lighting source. Prior to testing the samples were cleaned to remove any debris left over from the grind ing process. The light transmittance test is a nondestructive test and as such, the specimens from this test were re used for compress ion tests. The light test was carried out after 7 days of cu ring and the excess fiber and mortar was gr oun d smooth. A second light transmittance test was conducted after the use of a heat gun to melt the ends of the fiber optics, essentially polishing th em to theoretically allow a larger cone of light acceptance. Figure 4.3.1 1 : Light Transmittance Test Box Diagram To test the LTM, each test prism was 1 igure 4.3.1 One side of the box was left open, so the prisms c ould be loaded in the middle and a halogen light source can be placed exactly 12 inches

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47 away from the face of the test prism. The other side of the box was en closed as to not allow any external light inside, but ha d circular cut outs in order to place a light meter at predetermined heights. A light meter was used on both sides of the box to measure illuminance levels. On the light source side of the box, measurements were the bottom of the box), but directly in front of the masonry prism. On the output side, measurements were from the bottom but at the end of the box which was exactly 12 inches from the back face of the masonry prism. Figure 4.3.1 2 : Light Transmitt ance Test Box The equation for calculating transmitt ance can be found below and results are to be tabulated in the results section of this report : = ( / ) 100 Where: T = Transmittance percentage I = Transmitted Illuminance I o = Source Illuminance

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48 4. 3 2 Compressive Strength Test Compression testing of the prisms was performed after a 14 day curing time. The prism tests were per formed using a 220 kip capacity, M aterial T esting S ystem test frame in the UCD Structures Lab with a rotating spherical head that allowed for uniform loading even if the ends of the prisms were slightly out of parallel. The procedure began with installing t he prisms into the MTS testing machine to be compressed at a constant rate of 0.003 inches per second by a hydraulic ram The samples were loaded until failure occur red During the test the load and displacement data of the displaced plate was recorde d using a computer based data acquisition system to calculate the compressive strength. Subsequent to the testing of the final prism, a single brick was also compression tested, which provided for a baseline strength of the units. Figure 4.3.2: Te sting the Compression Strength of a Prism Because the bricks were obtained from an un labeled stockpile that was stored just outside of the CU Denver, Civil Engineering Testing Laboratory, their compressive strengths were unknown. However, as will be indi cated in the results section of this report, the tested

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49 compressive strength of a single brick was approximately 4300 psi. According to the TMS 602 (Masonry Standards Joint Committee, 2013), a prescriptive masonry strength can be derived and should be app roximately 1500 psi for a unit strength of 4150 psi and Type N mortar. This is true provide d that mortar joint widths do not exceed 5/8 inch as was the case for all of the test prisms. The capacity of masonry assemblages is dependent on the masonry compr essive strength, defined as the maximum compressive force resisted per unit of net cross sectional area of masonry (Masonry Standards Joint Committee 2013). This fundamental material property for a masonry assemblage can be determined by an empirical method where compressive strength is expressed as a function of the material properties of the individual components of the assembly (units, mortar and grout). Additionally, the compressive strength of masonry can be determined through testing of masonry prisms in accordance with ASTM C1314, ( Standard Test Method for Constructing and Testing Masonry Prisms Used to Determine Compliance with Specified Compressive Strength of Masonry ) In addition to the relevant data of comparative compressive strengths o f the various prisms, and those compressive strengths relative to that which is prescribed in TMS 602, given the number of data points, it was also possible to derive an approximate modulus of elasticity of the prisms. It is prescribed in TMS 602 that the modulus of elasticity of clay masonry assemblages is 700 times If the prescriptive equals 1500 psi and i s assumed to be valid, then the modulus of elasticity would be approximately 1050 ksi. The slope of the stress/strain curves was approximate d for each prism using data points at which

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50 the curves were most linear and compared to the prescribed elasticity, based upon the tested value. Like the brick prisms, the mortar cubes were allowed to cure for 14 days in the laboratory at normal humid ity levels. The mortar cubes were then compression tested using a 20 kip rated MTS test frame. The cubes were compressed at a constant rate of 0.001 inches per second until failure. 4. 3 .3 Shear Test There are no proper code specifications for testing s hear bond strength of masonry assemblages. Hence, a setup was made as shown in Fig ure 4.3.3 1 particularly to test the shear bond strength of the three brick prisms. Since the specimen should be inserted into the testing machine in such a manner that the load acts parallel to the mortar joint the test prism was turned on its side and compression tested in a 3 point bending setup. This was done using a 20 kip rated MTS test frame after a 14 day curing period as well. A small steel plate, roughly the siz e of the end of a single brick, was placed under a spherical head on the MTS ram in order to move the point of load application to a point as near the joint as possible in order to minimize the bending moment The center brick was then compressed by this steel plate and piston at a constant rate of 0.001 inches per second as the outer bricks were simply supported, allowing failure to occur in a slip format. It was thought that by laying the fiber optics parallel to only one axis and basically side by si de along the whole length of the joint, a slip plane would be created inside the mortar joint and along the fiber optics. However, as it will be reported in the results section, shear failure occurred along the bond of the brick and the composite mortar j oint.

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51 Figure 4.3.3 1 : Shear Test Setup The bond shear strength was determined as the arithmetic mean of all successful individual tests. A test was regarded as not su ccessful and discarded if the brick unit crushed during the test. The bond shear o was determined in the absence of normal stresses perpendicular to the mortar joint and by the following equation: o = F / (A1 + A2) Where: o = the bond shear strength F = the maximum force applied by the test machine A1 = the area of the upper joint A2 = the area of the lower joint The characteristic failure patterns shown in Fig ure 4 .3.3 2 were also recorded keeping in mind that intermediate patterns are possible. It is noted that the failure of a typical masonry assemblage usual ly occurs in the unit/mortar interface, being distributed either on on e or on two sides of the unit (Rilem, 1996) This type of failure is illustrated as failure pattern (a) in the figure below. It was thought that by adding a row of fiber optics inside the mortar, it would cause a failure pattern (b) as illustrated in the figure below. This would

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52 mean that the addition of fiber optics could cause a critical shear failure of LTM masonry assemblages not typically found in masonry assemblages without fibe r optics. Failure pattern (c) illustrated in the figure below demonstrates an extreme bond strength between the mortar and brick unit. This typically indicates an inferior strength of a brick unit itself and the measured value is considered the shear str ength of the brick, not the bond shear strength (Rilem, 1996) Figure 4.3.3 2: Shear Failure Patterns The failure patterns were visually inspected throughout all shear test specimens and documents in the results section of this report. These failur e patterns proved to be the main purpose of the shear test because bond shear strength can vary greatly and without reason from test to test. Although the bond shear strength was calculated and tabulated in the results section, pictures were also taken an d presented in the results section to be compared to the failure patterns in Figure 4.3.3 2.

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53 CHAPTER V RESULTS 5.1 Light Transmittances Although the transmitted measurements of the light transmittance tests were low by comparison to the source, the effect was pronounced when seen by the naked eye. Examples of the halogen light beam striking the faces of the prism can be seen in Figure 5.1 1a and the light transmittance through the fiber optics on the output side ca n be seen in Figure 5.1 1b Even a flash light from a basic smart phone illuminated the fiber optics within the mortar joints and could be seen in the daylight. However, the idea of light transmitting mortar is expected to achieve its full effect in the night or in low light setting s In stati ng this, the results of the measurements taken did behave as expected in the sense that the higher the fiber volumetric ratio, the higher the light transmitt ance a) b) Figure 5.1 1 : Inside the Light Test Box W hen the volumetric ratio was kept equivalent at about 5% then the best light transmittance on average was 42 lux from the 2.0 mm diameter fiber optics. A summary of

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54 the data co llected can be found in Table 5. 1 : Light Transmittance Test Results This da ta ca n vary due to the grinding and polishing procedures used during the fabrication of the prisms and is expressed as the averages over 4 sets of tests A rougher finish ed surface causes light to be transmitted in a diffuse pattern which is less efficient than a clean smooth finish and in turn could decrease the transmittance levels. It should also be noted that the fibers were laid individually and the curvature from the spool could have changed the angle at which the light was transmitted, effecting the read ings at the point the light meter was placed. Table 5.1: Light Transmittance Test Results

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55 The most interesting thing that the t esting revealed was that after applying the heat gun, transmittance increased anywhere from 1 42 % to 284% with the smaller di ameter fibers showing the most benefit from the heat gun. A graph of the increasing transmittance vs. the fiber volume ratio can be found in Figure 5. 1 2 and a second graph of varying the diameter of the fiber optics vs. the light transmittance ratio can be found in Figure 5 .1 3 Figure 5.1 2: Light Transmittance vs. Fiber Volumetric Ratio Figure 5.1 3: Light Transmittance vs. Fiber Optic Diameter 0.000% 0.050% 0.100% 0.150% 0.200% 0.250% 14.60% 9.73% 7.30% 4.87% 2.43% Mortar Only 0.089% 0.051% 0.020% 0.011% 0.010% 0.215% 0.134% 0.069% 0.042% 0.031% Percentage of Light Through Prism Ratio of Fiber optics to Mortar in Joint (by Area) *Diameter of Fiber Optics Vary Fiber Optic Volumetric Ratio vs. Light Transmittance Before Heat Gun After Heat Gun 0.000% 0.020% 0.040% 0.060% 0.080% 0.100% 0.120% 3.0 mm: 2.0 mm: 1.5 mm: 1.0 mm: Mortar Only 0.030% 0.031% 0.017% 0.011% 0.003% 0.074% 0.119% 0.063% 0.042% 0.003% Percentage of Light Through Prism Diameter of Fiber Optics (Equal CSA) *Fiber Optics Cross Sectional Area is about 5% of Joint Fiber Optic Diameter (Equal Volumetric Ratio) vs Light Transmittance Before Heat Gun After Heat Gun

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56 5.2 Compressive Strength A summary of the data collected can be found in Table 5 .2 : Compressive Strength Test Results This da ta can vary slightly due to the inexperience of masonry work and fabrication of the prisms, but all prisms were created by the same person and believed to be made as equivalents Table 5 .2 : Compressive Strength Test Results A graph of the compressive strength vs. the fiber volume ratio can be found in Figure 5.2 1 and a second graph of the compressive strength vs. the fiber weight ratio can be found in Figure 5.2 2 These graphs are based on the averages over four sets of testing. It appears if any ratio of fiber optic is added to a mortar joint, it substantially increases the maximum compression strength of the prism.

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57 Figure 5.2 1: Compressive Strength vs. Fiber Volumetric Ratio Figure 5.2 2: Compressive Strength vs. Fiber Weigh t Ratio 0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00 14.60% 9.73% 7.30% 4.87% 2.43% Mortar Only 74 69 72 68 69 55 Max Compression Force (Kips) Ratio of Fiber Optics to Mortar in Joint (by Volume) *Diameter of Fiber Optics Vary Fiber Optic Volumetric Ratio vs Compressive Strength 74 69 72 68 69 55 0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00 6.11% 4.04% 2.84% 2.39% 1.12% Mortar Only Max Compression Force (Kips) Ratio of Fiber Optics to Mortar in Joint (by Weight) *Averaged over 4 tests Weight Ratio vs Compressive Strength

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58 A graph of the assessment with equal fiber volumetric ratios, but varying the diameter of the fiber optics vs. the maximum compressive strength can be found in Figure 5.2 3 This graph was used to determine the best diameter of fiber optics that s hould be used based on the maximum compressive strength Figure 5.2 3: Compressive Strength vs. Fiber Optic Diameter 5.3 Shear Strength The r esults of the shear tests seem to have little variation depending on whether fiber optics were added to the join t or not. The failure pattern of each test prism can be seen in Figure 5.3 1 and all categorized as failure pattern (a) from Figure 4.3.3 2 in the pre vious section. All tests were categorized as this because the failure was along the bond between the bri ck and mortar, even though a couple cracks went directly through the mortar and continued along the bond line. In order to achieve failure pattern (b) and support the theory 69 69 76 68 55 0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00 3.0 mm: 2.0 mm: 1.5 mm: 1.0 mm: Mortar Only Max Compression Force (Kips) Diameter of Fiber Optics (Equal Volumetric Ratio) Fiber Optic Diameter vs Compressive Strength (Fiber Optics Volumetric Ratio is about 5% of Joint)

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59 that the addition of fiber optics had anything to do with the failure, the crack would need to propagate entirely inside the mortar joint and not along the bond line. a) No Fiber Optics b) 1mm Dia. Fiber Optics c) 1.5mm Dia. Fiber Optics d) 1.5 Dia. Fiber Optics e) 2mm Dia. Fiber Optics f) 3mm Dia. Fiber Optics Figure 5.3 1 : Results of Shear Failure T he results of the shear strength test and calculations of the bond shear strength are tabulated in Table 5. 3 and shown in Figure 5.3 2 The values o f specimen 1 were not included in the graph of Figure 5.3 2 because they came from a batch of mortar mix that had less water content and the joints specified The prisms

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60 created in Specimen 1 were the very first set c reated and was originally used more to determine the maximum number of fiber optics that could fit in a joint. The subsequent prism sets and batches of mortar were believed to have a more refined masonry work as t he learning process went along. However, the prisms from specimen 1 were also shown to fail in the same pattern and the results were believed to be applicable and worth showing. Table 5.3: Shear Strength Results Figure 5.3 2 : Bond Shear Strength vs. Fiber Volumetric Ratio 0 10 20 30 40 50 60 70 80 90 Mortar Only 2.43% 7.30% 9.73% 14.60% Shear Bond Strength, psi Volumetric ratio, % Bond Shear Strength vs. Fiber Volumetric Ratio

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61 CHAPTER VI CON CLUSION Light Transmitting Mortar is now an exciting and new innovation for the masonry effect, that will undoubtedly bring life to the idea of an old brick and mortar wall, but it has been shown to increase the structural properties to the overall assemblage as well. This added benefit might actually bring light to new possibilities of masonry construction and take brick walls out of being a just a veneer as they have seemed to bec ome. A summary and conclusions from t his experiment, as well as a few recommendations for future research can be found below for each section of the report. 6.1 Manufacturing Methods The fabrication process was extremely laborious and time consuming when completed by hand but there are a couple ideas that could address this issue. A fiber optic Light Transmitting Mesh could be created in standard sizes or rolls to allow masons to simply lay directly into the mortar as they carry on with their normal wor k. An automated process to straighten, cut, lay these pieces side by side (with about 2mm between each piece) and glue them together wo uld be a wise investment in terms of time savings and quality control. The hardest thing to deal with during this expe riment was by far the slight curvature inherent in the 5 inch pieces This was because the amounts of optical fibers ordered were delivered on large spools. Due to the fact that the manufacturer wound them onto spools as the plastic was extruded, i t le ft a permanent curvature in the fibers that was still seen during the process of pulling them off the spool and cutting them to such short lengths If a straight

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62 fibe r was to be used it would not only produce a better arrangement along the length of the br ick, but would also create a more uniform line of light transmittance on the other side of the wall. The grind ing process used a problem cutting off the excess fibers and mortar through most sized d iameters of the fiber optics However, the 3.0 mm diameter fiber was quite a bit more difficult than any other size because it made the grinder jump from fiber to fiber as it cut through each one and caus ed marks to be left on the brick units. Any size s maller than the 3.0 mm diameter fiber optics cut extremely smooth with the masonry disc 6. 2 Light Transmittance The light transmitting mortar performed as expected during the light transmittance tests with an increase in light transmittance as the fiber volume tric ratio increased. Further improvements could be made by using higher grade optical fibers and a better way to polish the ends to reduce the number of imperfections on the exposed faces of the fibers. Although it was a little surprising the ligh t meter gave as low values of light transmittance as was recorded, tests were double checked and spot checked on different days to verify the results. It was only surprising because the effect seen by the naked eye was quite a bit better than expected. E ven before the ends were gr ound smooth and with excess mortar partiall y covering the ends, visible light was seen and gave a twinkling effect. This leads me to the conclusion that even during weathering and harsh outdoor conditions, LTM will continue to g ive the desired effect over long periods of time. Although it was not tested during this

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63 report, it is believed that the fiber optic elements would stand up to cleaning and power washing procedures just as well as brick and mortar does on current walls. Even though it was demonstrated that increasing the fiber volumetric ratio increased the light transmittance, it was also shown that simply increasing the quantity of the same diameter fiber optics did not necessarily increase the light transmittance line arly. Since this is thought to be true, there does not seem to be any benefit in packing in large quantities of fiber optics into a single joint. When equal volumetric ratios were tested based solely on varying the diameter of the fiber optics, it appea rs that the best selection to be used in a final product would be the 2.0 mm diameter fiber optic. This conclusion is based solely on the light transmittance test. 6. 3 Compressive Strength The results from the compressive strength tests showed that the a ddition of any size or quantity of fiber into a mortar joint substantially increases the compressive strength of the overall assemblage This is thought to be true because the added tensile strength of fiber. During a compression test of the masonry assemb lages, failure occurs due to the development of tensile stress in the masonry unit or bricks. Bricks and mortar will sustain v ) is defined as the ratio of transverse deformation, or strain, to axial deformation, and is higher for mortar than it is for the bricks. Therefore, when the assemblage is compressed, the transverse deformation of the mortar is resisted by the bricks; putting the mortar into triaxial compression and the bricks into bilateral tension Since all actions have equal and opposite reactions, transverse tensile stresses develop in the bricks because the brick s tensile strength

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64 is lower than the compressive strengths of the whole assemblage. Thus, tensile splitting of the prism is the controlling failure mode as shown in F igure 6. 3 1 The addition of the fiber optics in this composite material is thought to be were the LTM got its additional strength. Since fibers have sup e r io r tensile strength, it was believed tha t they acted as reinforcement to the overall composite assemblages when the brick units experienced the critical tensile stresses. Figure 6.3 1 : Failure Mode in Brick Prism Figure 6.3 2: Tensile Splitting during Compression testing In all tested sp ecimens, tensile splitting of the bricks was observed. Moreover, the tensile splitting occurred at the approximate locations of the cores, which was expected due

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65 to the reduced cross sectional area of brick at those locations. This type of failure is ill ustrated in the photographs above. It should be noted that t he surfaces of the prisms tested during this report were not always completely parallel to each other and could help explain why there was variation in compressive strength results. This was th e reason that 4 sets of tests were carried out for each volumetric size and variation of diameter in the fiber optics. On average, the results proved to be consistent with fiber reinforced mortar leading to an increase in prism compressive strength. How ever, t he maximum compression values do not substantially increase as the fiber volumetric ratio was increased. Moreo ver, from the results of varying the diameter of the fiber optics only and keeping the fiber volumetric ratio the same, it appears that t he best selection to be used in a final product would be the 1.5 mm diameter fiber optic. This conclusion is based solely on the compression test. 6.4 Shear Strength From t he results of the shear test it was evident that all test prisms failed in the bonding of the mortar to brick It was not seen that the addition of any quantity of fiber optics in a joint of mortar weakened the assemblage an any additional way. This is believed to be true given the small diameter of the fiber optics and the fact mo rtar was allowed to encapsulate the fiber completely. It is thought that if fiber optics were laid side by side, touching continuously from end to end of a joint, the possibility of shear failure could occur along this plane but did not prove this effect to be true However, i t is recommended that at least a 1.0 mm space be left between each piece of fiber optic.

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66 6.5 Final Thoughts Combining this information with the conclusion sections above, it is thought that either the 1.5 mm or 2.0 mm diameter f ibers are more than suitable for the design of LTM and the final selection should be based on personal preference for the look and quantity of light pixels the architect or owner desires. It is recommended that if the 1.5 mm fiber optic is chosen then 70 pieces should be used per joint and 40 pieces for the 2.0 mm fiber optics. Based on these numbers, t he more economical choice would be the 1.5 mm diameter because there is 2,296 feet on a spool and a manufacturer would be able to make 79 joints worth of material. Whereas, the 2.0 mm diameter fiber optics comes in spools of 1,148 feet and 69 j oints could be made per spool. Each spool was purchased for $105 no matter the size at the time of this report In conclusion, t he development of translucent conc rete has paved the way for fiber optics in other materials such as mortar. The fact that the addition of fiber optics not only substantially increases the strength, but also allows for light to be effectively transmitted through mortar, I believe a produc t like this will be useful to architects and engineers alike.

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67 R EFERENCES Ahuja, Aashish, Mosalam, Khalid M., Zohdi, Tarek I. (2015) Journal of Architectural Engineering, Vol. 21, Issue 2, June 201 5: http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29AE.1943 5568.0000167#sthash.EkTAK31Z.dpuf ALI, ABID (2014) Oct, 20 th 2014 https://es.slideshare.net/abidalimahar52/original litracon Bates Daniel (2011) s DailyMail.com January, 5 th 2011 http://www.dailymail.co.uk/sciencetech/article 13443 83/Transparent light cement lets light flood room.html#ixzz4o972a9Qk Fathima, S., Tech B., (2015) T.K.M Institute of Technology https://www.slideshare.net/SahlaFathima/seminar report 53878460 Goho, A. (2005). Concrete Nation: Bright future for ancient material. Science News Vol. 167, No. 1, p. 7, Jan. 1, 2005 http://www.concretew ashout.com/downloads /Concrete_Nation__Sc ien ce_News_Online,_J an._1,_2005.pdf Hamid, D. A. 3 rd Ed. Boulder, CO: The Masonry Society Italcementi Group. Available: http://www.italcemen tigroup.com/ENG/Medi a+and+Communication/ News/Corporate+event s/20100322. htm LitraCon. Available: http://www.litracon. hu/projects.php Lucem. Available: http://www.lucem.de/ index.php?id=156&L=1 New York : Spon Press. Masonry Standards Joint Committ Structures (TMS Longmont, CO McGillivray, Sara (2011) Translucent Concrete: An Emerging Material December 9th, 2011 http://illumin.usc.edu/245/translucent concrete an emergi ng material/

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68 News Desk (2013) A New Innovation in Concrete September 30, 2013 http://www.masterbuilder.co.in/light transmitting concrete pan els a new innovation in concrete technology Pagliolico Simonetta L., Lo Verso, Valerio R.M., Torta, Annalisa Giraud, Maurizio ., Canonico, Fulvio ., Ligi, Laura ( 2015) Energy Procedia Volume 78 November 2015, Pages 1811 1816 https://doi.org/10.1016/j.egypro.2015.11.317 RILEM MS D.6 (1996) In situ measurement of masonry bed joint shear strength. RILEM TC 127 MS: Tests form masonry materials and structures, Volume 29, October 1996, pp. 459 475. Sabhapathy, K.S. (2014 A PR 27 TH 2014 https://www.slideshare.net/sabadinesh/transparent concrete translucent System, method and apparatus for providing lane separation and traffic U.S. Patent No. 14/878,583 (2015) Saleem, Muhammad Elshami, Mostafa Morsi Najjar, Muhammad (2017) Development, Testing, and Implementation Strategy of a Translucent Concrete Based Smart Lane Journal of Construction Engineering and Management Vol. 143, I ssue 5, May 2017 http://ascelibrary.org/doi/abs/10.1061/(ASCE)CO.1943 7862.0001240#sthash.N7RQNryD.dpuf Schariff, R. (1989) lin g Publishing Company Shanmugavadivu, P.M., Scinduja, V., Sarathivelan, T., Shudesamithronn, C.V (2014) : IJRET: International Journal of Research in Engineering and Technology, Volume: 03, Special Issu e: 11, June 2014 The Economist. ( 2001) How to see through walls: Transparent concrete is encouraging architects to rethink how they design buildings. Sept. 20, 2001 http://www.economist .com/node/77942 1

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69 APPENDI X Appendix A: Light Transmittance Test (Varying Fiber Volumetric Ratio) Photos Light Source Before Heat gun After Heat Gun Figure A.1 N o Fiber Optics Light Source Before Heat gun After Heat Gun Fig ure A. 2 1 mm Dia. Fiber Optics (75 per Joint)

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70 Light Source Before Heat gun After Heat Gun Figure A. 3 1mm Dia. Fiber Optics (150 per Joint) Light Source Before Heat gun After Heat Gun Figure A. 4 1.5 mm Dia. Fiber Optics (100 per J oint)

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71 Light Source Before Heat gun After Heat Gun Figure A. 5 2mm Dia. Fiber Optics (75 per Joint) Light Source Before Heat gun After Heat Gun Figure A. 6 3mm Dia. Fiber Optics (50 per Joint)

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72 Appendix B: Light Transmittance Tes t (Equal Fiber Volumetric Ratio) Photos Light Source Before Heat gun After Heat Gun Figure B.1 1.5mm Dia. Fiber Optics (70 per Joint) Light Source Before Heat gun After Heat Gun Figure B.2 2mm Dia. Fiber Optics (40 per Joint)

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73 Lig ht Source Before Heat gun After Heat Gun Figure B.1 3mm Dia. Fiber Optics (20 per Joint)

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74 Appendix C : Compression Test (Varying Fiber Volumetric Ratio) Photos Figure C.1 No Fiber Optics Figure C.2 1 mm Dia. Fiber Optics (75 pe r Joint)

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75 Figure C.3 1mm Dia. Fiber Optics (150 per Joint) Figure C.4 1.5 mm Dia. Fiber Optics (100 per Joint)

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76 Figure C.5 2mm Dia. Fiber Optics (75 per Joint) Figure C.6 3mm Dia. Fiber Optics (50 per Joint)

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77 Appendix D : Compr ession Test (Equal Fiber Volumetric Ratio) Photos Figure D.1 1mm Dia. Fiber Optics (150 per Joint) Figure D.2 1.5mm Dia. Fiber Optics (70 per Joint)

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78 Figure D.3 2mm Dia. Fiber Optics (40 per Joint) Figure D.4 3mm Dia. Fiber O ptics (20 per Joint)

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79 Appendix E : Prism Compression Data Varying Fiber Volumetric Ratio Specimen Max Force Max Stress (9 7) No Fiber 49.71 kips 1,798.38 psi Figure E .1 Stress Strain Curve for No Fiber Prism Specimen Max Fo rce Max Stress (9 9) No Fiber 52.40 kips 1,895.65 psi Figure E 2 Stress Strain Curve for No Fiber Prism 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain

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80 Specimen Max Force Max Stress (9 11) No Fiber 53.84 kips 1,947.98 psi Figure E 3 Str ess Strain Curve for No Fiber Prism Specimen Max Force Max Stress (9 12) No Fiber 64.59 kips 2,336.88 psi Figure E.4 Stress Strain Curve for No Fiber Prism 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain

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81 Specimen Max Force Max Stress (9 7) 1mm 75 55.78 kips 2,017.92 psi Figure E. 5 Stress Strain Curve for 1mm (75 per Joint) Prism Specimen Max Force Max Stress (9 9) 1mm 75 70.53 kips 2,551.64 psi Figure E. 6 Stress Strain Curve for 1mm (75 per Joint ) Prism 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain

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82 Specimen Max Force Max Stress (9 11) 1mm 75 67.84 kips 2,454.27 psi Figure E. 7 Stress Strain Curve for 1mm (75 per Joint) Prism Specimen Max Force Max Stress (9 12) 1mm 75 82.93 kips 3 ,000.13 psi Figure E. 8 Stress Strain Curve for 1mm (75 per Joint) Prism 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain

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83 Specimen Max Force Max Stress (9 7) 1mm 150 63.35 kips 2,291.81 psi Figure E. 9 Stress Strain Curve for 1mm (150 per Joint) Prism Specimen Max Force Max Stress (9 9) 1mm 150 55.29 kips 2,000.38 psi Figure E. 10 Stress Strain Curve for 1mm (150 per Joint) Prism 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain

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84 Specimen Max Force Max Stress (9 11) 1mm 150 72.41 kips 2,619.80 psi Fig ure E. 11 Stress Strain Curve for 1mm (150 per Joint) Prism Specimen Max Force Max Stress (9 12) 1mm 150 79.11 kips 2,862.23 psi Figure E. 1 2 Stress Strain Curve for 1mm (150 per Joint) Prism 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain

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85 Specimen Max Force Max St ress (9 7) 1.5mm 100 65.84 kips 2,381.94 psi Figure E. 13 Stress Strain Curve for 1.5mm (100 per Joint) Prism Specimen Max Force Max Stress (9 9) 1.5mm 100 60.54 kips 2,190.21 psi Figure E. 14 Stress Strain Curve for 1.5mm (100 per Joint) Prism 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain

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86 Specimen Max Force Max Stress (9 11) 1.5mm 100 68.29 kips 2,470.48 psi Figure E. 15 Stress Strain Curve for 1.5mm (100 per Joint) Prism Specimen Max Force Max Stress (9 12) 1.5mm 100 91.92 kips 3,325.58 psi Figure E. 16 Stress Strain Curve for 1.5mm (100 per Joint) Prism 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain

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87 Specimen Max Force Max Stress (9 7) 2mm 75 64.35 kips 2,327.95 psi Figure E. 17 Str ess Strain Curve for 2mm (75 per Joint) Prism Specimen Max Force Max Stress (9 9) 2mm 75 61.13 kips 2,211.56 psi Figure E. 18 Stress Strain Curve for 2mm (75 per Joint) Prism 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain

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88 Specimen Max Force Max Stress (9 11) 2mm 75 71.91 kips 2,601.69 psi Figure E. 19 Stress Strain Curve for 2mm (75 per Joint) Prism Specimen Max Force Max Stress (9 12) 2mm 75 78.29 kips 2,832.56 psi Figure E. 20 Stress Strain Curve for 2mm (75 per Joint) Prism 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain

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89 Specimen Max Force Max Stress (9 7) 3mm 50 69.46 kips 2,512.84 psi Figure E. 21 Stress Strain Curve for 3mm (50 per Joint) Prism Specimen Max Force Max Stress (9 9) 3mm 50 70.33 kips 2,544.46 psi Figure E. 22 Stress Strain Curve for 3mm (50 per Joint) Prism 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain

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90 Specimen Max Force Max Stress (9 11) 3mm 50 76.59 kips 2,771.08 psi Figure E. 23 Stress Strain Curve for 3mm (50 per Joint) Pri sm Specimen Max Force Max Stress (9 12) 3mm 50 81.22 kips 2,938.35 psi Figure E. 24 Stress Strain Curve for 3mm (50 per Joint) Prism 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% Stress (psi) Strain (in/in) Stress vs Strain

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91 Appendix F : Prism Compression Data Equal Fiber Volumetric Ratio Specimen Max Force Max Stress (9 7) 1mm 150 63.35 kips 2,291.81 psi Figure F 1 Stress Strain Curve for 1mm (150 per Joint) Prism Specimen Max Force Max Stress (9 9) 1mm 150 55.29 kips 2,000.38 psi Figure F.2 Stress Strain Curve for 1mm (150 per Joint) Prism 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain

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92 Specimen Max Force Max Stress (9 11) 1mm 150 72.41 kips 2,619.80 psi Figure F.3 Stress Strain Curve for 1mm (150 per Joint) Prism Specimen Max Force Max Stress (9 12) 1mm 150 79.11 kips 2,862.23 psi Figure F.4 Stress Strain Curve for 1mm (150 per Joint) Prism 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain

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93 Specimen Max Force Max Stress (9 7) 1.5mm 70 71.05 kips 2,570.34 psi Figure F.5 Stress Strain C urve for 1.5mm (70 per Joint) Prism Specimen Max Force Max Stress (9 9) 1.5mm 70 67.82 kips 2,453.53 psi Figure F.6 Stress Strain Curve for 1.5mm (70 per Joint) Prism 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain

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94 Specimen Max Force Max Stress (9 11) 1.5mm 70 83.54 kips 3,022.54 psi Figure F.7 Stress Strain Curve for 1.5mm (70 per Joint) Prism Specimen Max Force Max Stress (9 12) 1.5mm 70 79.76 kips 2,885.61 psi Figure F.8 Stress Strain Curve for 1.5 mm (70 per Joint) Prism 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain

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95 Specimen Max Force Max Stress (9 7) 2mm 40 14.70 kips 531.91 psi Figure F 9 Stress Strain Curve for 2mm (40 per Joint) Prism Specimen Max Force Max Stress (9 9) 2mm 40 65.46 kips 2,368.32 psi Figure F.10 Stress Strain Curve for 2mm (40 per Joint) Prism 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain

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96 Specimen Max Force Max Stress (9 11) 2mm 40 69.40 kips 2,510.91 psi Figure F.11 Stress Strain Curve for 2mm (40 per Joint) Pri sm Specimen Max Force Max Stress (9 12) 2mm 40 68.08 kips 2,462.87 psi Figure F.12 Stress Strain Curve for 2mm (40 per Joint) Prism 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain

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97 Specimen Max Force Max Stress (9 7) 3mm 20 48.69 kips 1,76 1.70 psi Figure F.13 Stress Strain Curve for 3mm (20 per Joint) Prism Specimen Max Force Max Stress (9 9) 3mm 20 58.59 kips 2,119.88 psi Figure F.14 Stress Strain Curve for 3mm (20 per Joint) Prism 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain

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98 Specimen Max For ce Max Stress (9 11) 3mm 20 65.08 kips 2,354.68 psi Figure F.15 Stress Strain Curve for 3mm (20 per Joint) Prism Specimen Max Force Max Stress (9 12) 3mm 20 73.65 kips 2,664.51 psi Figure F .16 Stress Strain Curve for 3mm (20 per Joint) Prism 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain 0 500 1000 1500 2000 2500 3000 3500 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% 1.60% 1.80% Stress (psi) Strain (in/in) Stress vs Strain

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99 Appendix G : Mortar Cube Compression Test Photos Figure G.1 1 st Batch of Mortar Figure G.2 3 rd Batch of Mortar

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100 Appendix H : Mortar Cube Compression Data Specimen Max Force Max Stres s (9 7) Mortar Cube 6.29 kips 1,573.09 psi Figure H.1 Stress Strain Curve for 1 st Mortar Cube Specimen Max Force Max Stress (9 9) Mortar Cube 3.26 kips 815.86 psi Figure H.2 Stre ss Strain Curve for 2 nd Mortar Cube 0 200 400 600 800 1000 1200 1400 1600 1800 2000 0.00% 1.00% 2.00% 3.00% 4.00% 5.00% 6.00% Stress (psi) Strain (in/in) Stress vs Strain 0 100 200 300 400 500 600 700 800 900 1000 0.00% 1.00% 2.00% 3.00% 4.00% 5.00% 6.00% Stress (psi) Strain (in/in) Stress vs Strain

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101 Specimen Max Force Max Stress (9 11) Mortar Cube 5.47 kips 1,080.79 psi Figure H.3 Stress Strain Curve for 3 rd Mortar Cube Specimen Max Force Max Stress (9 12) Mortar Cube 8.94 kips 1,765.35 psi Figure H.4 Stress Strain Curve for 4 th Mortar Cube 0 200 400 600 800 1000 1200 0.00% 1.00% 2.00% 3.00% 4.00% 5.00% 6.00% Stress (psi) Strain (in/in) Stress vs Strain 0 200 400 600 800 1000 1200 1400 1600 1800 2000 0.00% 1.00% 2.00% 3.00% 4.00% 5.00% 6.00% Stress (psi) Strain (in/in) Stress vs Strain

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102 Appendix I : Shear Test Photos Figure I .1 No Fiber Optics Figure I .2 No Fiber Optics

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103 Figure I .3 1mm Dia. Fiber Optics (150 per Joi nt) Figure I .4 1.5 mm Dia. Fiber Optics (100 per Joint)

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104 Figure I .5 1.5 mm Dia. Fiber Optics (100 per Joint) Figure I .6 2mm Dia. Fiber Optics (75 per Joint)

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105 Figure I .7 3mm Dia. Fiber Optics (50 per Joint)

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106 Appendix J: Shear Test Data Specimen Max Force Max Stress (9 15) No Fiber 2.93 kips 106.10 psi Figure J .1 Stress Strain Curve for No Fiber Prism Specimen Max Force Max Stress (10 3) No Fiber 3.87 kips 140.17 psi Figure J 2 Stress Strain Curve for No Fiber Pri sm 0 20 40 60 80 100 120 140 160 180 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% Stress (psi) Strain (in/in) Stress vs Strain 0 20 40 60 80 100 120 140 160 180 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% Stress (psi) Strain (in/in) Stress vs Strain

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107 Specimen Max Force Max Stress (10 3) 1mm 75 4.68 kips 169.46 psi Figure J.3 Stress Strain Curve for 1.5mm (75 per Joint) Prism Specimen Max Force Max Stress (9 15) 1mm 150 0.96 kips 34.80 psi Figure J 4 Stress Strain Curve for 1mm (1 50 per Joint) Prism 0 20 40 60 80 100 120 140 160 180 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% Stress (psi) Strain (in/in) Stress vs Strain 0 20 40 60 80 100 120 140 160 180 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% Stress (psi) Strain (in/in) Stress vs Strain

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108 Specimen Max Force Max Stress (9 15) 1.5mm 100 2.08 kips 75.21 psi Figure J.5 Stress Strain Curve for 1.5mm (100 per Joint) Prism Specimen Max Force Max Stress (10 3) 1.5mm 100 4.64 kips 168.00 psi Figure J.6 Stress Strain Curve for 1.5mm (100 per Joint) Prism 0 20 40 60 80 100 120 140 160 180 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% Stress (psi) Strain (in/in) Stress vs Strain 0 20 40 60 80 100 120 140 160 180 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% Stress (psi) Strain (in/in) Stress vs Strain

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109 Specimen Max Force Max Stress (10 3) 2mm 75 2.99 kips 108.27 psi Figure J.7 Stress Strain Curve for 2mm (75 per Joint) Prism Specimen Max Force Max Stress (10 3) 3mm 50 4.65 kips 168.22 psi F igure J.8 Stress Strain Curve for 3mm (50 per Joint) Prism 0 20 40 60 80 100 120 140 160 180 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% Stress (psi) Strain (in/in) Stress vs Strain 0 20 40 60 80 100 120 140 160 180 0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40% Stress (psi) Strain (in/in) Stress vs Strain